orly going thirty

Arduino Bluetooth Digital Setting Circles for Telescope

2012-01-11T01:20:00.006+08:00

I decided to build an Arduino digital setting circle for my mount because it's really hard to buy Tangent Instruments boxes cheaply, and the Argo Navis (the Lexus of telescope digital setting circles) is quite expensive. Besides it seemed like a cool project.

I used an Arduino Uno, which cost $32 (Singapore dollars)

an Arduino Proto Shield ($5), as well as some headers ($2)

I got an RJ-45 jack from Sim Lim Tower and soldered it to the Proto Shield. Obviously four (4) digital pins from the Arduino are needed to read the two encoder channels. A lesson painfully learned: do not use pins 0 and 1 (the serial RX and TX pins) for anything else!

Jim's Mobile (JMI) has some good documentation on the pinout of the RJ-45 encoder connector. By maintaining compatibility with the JMI/Tangent Instruments encoder cable, I ensured that my Arduino DSC is compatible with all the telescope encoder setups out there.

I used Mike Fulbright's Arduino DSC source code, although his code didn't implement 4X quadrature decoding, only 2X which results in half the encoder resolution.

In order to get 4X quadrature, you need to hook interrupts to both channels of the encoder. Since there are two encoders (RA and DEC), you need four (4) interrupts - but the basic Atmega328p CPU on the Arduino only has two interrupts. To get my four interrupts, I used the PinChangeInt library, which provides multiple virtual interrupts.

A side-effect of this choice of library is that my code won't compile on the Digilent Max32 which is a 32-bit Arduino-compatible board. I had bought this board because I wanted to make a full GoTo controller and thought I needed more RAM (the Arduino Uno only has 2K of RAM and an 8-bit processor, the Max32 has 512K of RAM and a 32-bit processor).

I also soldered a $9.95 "linvor" Bluetooth serial adapter from ebay to the Arduino proto shield and (breaking my earlier rule) wired the Bluetooth RX to the Arduino TX pin, and the Bluetooth TX to the Arduino RX pin.

A good overview of how to use these cheap Bluetooth dongles with the Arduino is here. Note that it is necessary to disconnect the proto shield from the Arduino Uno board when uploading code to the board, since the programming circuit and the Bluetooth board fight each other for control of the Arduino's serial pins (pins 0 and 1).

I then powered the Arduino DSC from a 12V supply and connected it to the RA and DEC encoders on my mount:

Actually I also put a DFRobot LCD Keypad Shield on it so I could eyeball the RA and DEC encoder readings. Although for the "production" version this is completely unnecessary because the encoder counts are polled by a PC.

Pairing the "linvor" Bluetooth dongle with the PC is trivial and beyond the scope of this article, but suffice it to say that the Arduino DSC was accessible on COM4 on my PC. I was able to verify its operation using Putty (RealTerm didn't work and persistently disconnected the Bluetooth connection, avoid!)

I used Dave Ek's ASCOM driver for digital setting circles and Cartes du Ciel planetarium software.

Basically, you configure Cartes du Ciel (or any Windows planetarium software that supports ASCOM) to connect to the telescope, select the Dave Ek ASCOM driver, select COM4 (or whatever COM port the Arduino DSC gets assigned by the Bluetooth subsystem) and align.

After a successful alignment, when you move the telescope mount around and the encoders change readings, Cartes du Ciel will update its on-screen reticle to correctly reflect where the telescope is pointing. Cool!

This DSC should also work with SkySafari for Android which supports Tangent Instruments-type encoders over Bluetooth. I'll test this out when I get my hands on an Android 2.2 device.

The nice thing about this DSC (as compared to say Dave Ek's DSC circuit) is that the amount of soldering and PCB-etching required is close to nil: all you need is an RJ-45 jack, the Bluetooth dongle, an Arduino Uno, a Proto Shield, and the headers.

The Arduino Uno at about $25 USD is so darn cheap that it doesn't make sense to knock yourself out etching your own PCB and soldering tiny parts to it. This DSC does require some soldering - the RJ-45 jack, headers, and Bluetooth dongle - but that's quite minimal. And the total cost is well under $100, under $50 even. Most folks want $150 plus for their old Tangent Instruments boxes, so as long as you have a laptop already or Android device, you're golden. And I always have a laptop with my mount anyway, since I use the laptop for image capture and guiding.

Poor Man's Vixen Starbook

2011-12-28T02:51:00.003+08:00

Here is how I butchered a NGC Sky Vector Digital Setting Circle (DSC) to connect it to a SkyWire.

SkySafari from Southern Stars is a great planetarium application for the Apple devices and now Android. It's the closest to the old Starry Night Backyard that I knew and loved a decade ago.

One of the neat tricks that SkySafari has is its ability to control most any telescope via a wireless dongle called a SkyFi, or a cheaper wired serial dongle called a SkyWire:

The SkyWire is basically a serial port that connects to the port on the bottom of every iPod, iPhone, and iPad out there.

I had already previously used the SkyWire to control my Celestron CGEM mount, but the CGEM is currently in the doghouse because its GoTo's are darn unreliable. I already had an NGC Sky Vector that I snagged for a hundred bucks off Astromart. The Sky Vector has an RJ-11 jack for a serial connector to a PC (or SkyWire) but I didn't have an RJ-11 plug (or crimper) handy. I did however have a DB-9 female connector, so I decided to swiss-cheese the Sky Vector casing.

Before:

After two runs with a 6mm drill bit:

And much later after much dremel-ing:

The Sky Vector PCB (note the little Tangent Instruments label) with its vacuum-fluorescent display and minimalistic four-button interface:

Contrary to my belief (which caused a lot of head-scratching and gnashing of teeth) the RJ-11 jack is soldered to both sides of the PCB, and the correct pins to solder to.. are not obvious. Only three wires are needed: RX, TX, and GND. And I got them all wrong.

The correct pinout according to Southern Stars. Use the third column ("Southern Stars SkyFi") and fifth column ("Celestron, Astromaster, others").

So basically it's DB9 pin 3 to RJ-11 pin 3; DB-9 pin 5 to RJ-11 pin 4 (this is the ground pin); and DB-9 pin 2 to RJ-11 pin 2. More information albeit with not as nice-looking diagrams.

After several bouts of soldering:

Buttoned it up..

and in action (telescope mount not shown):

I noticed that SkySafari couldn't talk to the Sky Vector initially (although I could using a USB serial adapter and RealTerm which is a good HyperTerminal replacement). Turns out my V 3.65 Sky Vector doesn't respond to queries about its maximum encoder resolution, I had to hard-code these into SkySafari.

Next stop.. real alignment. Weather's pretty bad so I just did a simulated/fake align to verify operation.

The nice thing about SkySafari is that you can sync on anything on the screen. Doesn't have to be from a small list of alignment stars.

Wood Low-Latitude Wedge for AP600E

2011-12-18T22:25:00.002+08:00

The Astro-Physics 600E equatorial mount is not designed to go as low as 1 degree Latitude, where I live. Unfortunately the 900WDGA low-latitude wedge for the AP900 is not compatible with the AP600, and the successor to the AP600E (the Mach1 GTO) doesn't need a wedge to reach low latitudes.

I had a company in Malaysia fabricate a low-latitude wedge for my CGEM, but as I am not traveling to Malaysia anytime soon, I could not get one made for my AP600. Instead, I decided to make one myself out of wood.

The parts were a shelf board from Home-Fix DIY Shop (S$11) and two 8" diameter wood chopping boards from Carrefour (S$7.50 each). I cut a couple of angled pieces from the shelf board, sanded them down to get them flat and consistent, then glued them to one of the chopping boards. I also put a flat piece in-between the angled pieces for strength.

After attaching the top chopping board (also with epoxy) I drilled three holes 120 degrees apart and screwed M6 threaded inserts into the holes.

This allowed me to use hex-head M6 bolts to attach the ADATRI to the top of the wedge.

Another view:

This is what it looks like in action:

The setup is still shaky, but I don't know if it's my wedge, or the aluminum surveyor tripod. I'm planning to purchase a Takahashi SE-S wood tripod locally although haven't gotten around to it. Hopefully that tripod in conjunction with my wooden wedge, will be stable enough.

How to take a proper flat

2011-12-06T01:45:00.004+08:00

Flats are necessary to eliminate vignetting and dust spots on your camera or CCD sensor when doing astrophotography.

I wrote an entire essay all about flats for my Swinburne astronomy course, but that's neither here nor there.

Here's a primitive but fairly effective way of getting a "dome flat."

All you need is your entire imaging train (telescope, flattener and filters if required, and CCD camera or DSLR), a sheet of white paper, and your friendly laptop.

The key things to remember are:

1. The telescope must be right up against the laptop screen (which should be displaying a blank white page, like a blank PowerPoint slide)

2. You should put a sheet of paper against the laptop screen to diffuse the light a bit

3. The CCD integration time (exposure time) must be more than 2 seconds. The reason for this is that at short integration times, all sorts of weird visual artifacts show up on the laptop screen, kind of like the "rolling picture" of old-time TV's when you see them in movies

4. Take at least four flats, rotating the entire telescope by 90 degrees between flats. Your software (I use DeepSkyStacker) should average these four flats to create a master flat.

A picture is worth a thousand words:

Mount Periodic Error

2011-11-22T23:36:00.002+08:00

I finally learned how to correctly measure periodic error of German Equatorial Mounts.

Some of the things I've learned: you need to turn off guiding output in PHD, otherwise what you are measuring is the error with auto-guiding turned on. And, you need to correct for the declination of the star you are guiding on (stars closer to the poles would show less periodic error as they move through shorter "arcs").

I've also learned how to use WebCamScheinern for somewhat automated drift polar alignment, and managed to get good alignments these past two weeks. And, I've also learned to use PEMPro (albeit a trial version for now) to measure periodic error and generate the curves.

With that said, here are the periodic errors of the three mounts I currently own. The Vixen Polaris is gone, sold to a guy in Manila, and I wouldn't bother measuring the periodic error of the Orion EQ-1 that's rusting under the sink.

Vixen Great Polaris with DD-1 stepper motor controller and two MT-1 steppers:

That's a whopping 85 arc-seconds peak-to-peak! a far cry from the 20 arc-seconds I wishfully "measured" some months ago..

Celestron CGEM:

29 arc-seconds peak-to-peak. Not too shabby, and smooth enough.

Astro-Physics 600E QMD, probably manufactured when I was still at university:

7.84 arc-seconds peak-to-peak. A pretty good figure, although I believe the G11 can match or exceed this performance (a used G11 would also cost a bit less, and crucially, carry much more payload). I'm trying to upload the PEM curve to this mount and see how low that figure can go..

Check Engine Light

2011-08-05T19:42:00.003+08:00

Got the dreaded CEL (Check Engine Light) a few days ago. It initially started as some burbling during idle, degraded to severe misfiring and lack of power going up a grade (accompanied by a flashing CEL, which is the worst), and after that a solid CEL, rough and fluctuating idle, and the motive power of a motorcycle.

'Twas a bit of an adventure tooling around in limp mode, I certainly didn't break any speed limits for a couple days (and could not, even if I wanted to). Luckily replacement of the four spark plugs with new ones cleared everything up.

Back to 150 horsepower.

Grom Audio iPod/iPhone Adapter Installation

2011-07-23T18:06:00.010+08:00

Lalai and I recently came upon (cough, cough!) an old-ish used car. Because it is too old, the factory head unit does not have MP3 capability (making this head unit inferior to the one in our Mazda3 back in Manila).

My original idea was to purchase a replacement 2-DIN head unit that had an iPod port and GPS connectivity. Unfortunately, Lalai and I had already bought a TomTom XXL 550 that would be made redundant, the Pioneer DVD/GPS HU is quite expensive, and I would need a replacement dash fascia since the OEM head unit is integrated into the car's dash.

Because of these problems (and the practical one of budget!) I decided to purchase an iPod adapter from Grom Audio, specifically, their iPod/iPhone Adapter V3, which cost US$100 plus under S$20 shipping from the US via ComGateway. They do sell the thing for US$100 but I got it from their e-Bay store for US$90. That's a couple lunches saved right there!

This is how I installed it.

First order of business is to remove the glove box. This is fairly trivial to do (and completely tool-less) and is also required to change the cabin filter.

For the completely hopeless, our friends at Honeywell (proud makers of HEPA filters and similar asthma-friendly gadgets) have this video on replacing the cabin filter:

There are a lot of instructions on the net for installing the Grom (and similar) adapters, such as this one. However, all of these instructions require removing the center cup holder, gear shift, and center console. On all the DIY forums on this topic, there are a few elusive postings who claim that you don't need to remove the center console to install the Grom.

I can confirm, that on right-hand-drive cars it is trivial to plug the OEM HU-to-Grom cable into the back of the Panasonic head unit through the glove box. The Panasonic CD changer port is on the left side of the head unit, next to the FM antenna, and is easily reachable if you have small hands.

However if you have large hands, it's a different story. Same for left-hand-drive cars, where you would need to get at the head unit from the driver's side (no handy glove box to remove).

Here's a photo of the OEM HU-to-Grom cable, already plugged into the head unit, and dangling out of the glove box area.

I decided to sanity-check the setup before closing things up, so I connected everything together and tried playing some music. Everything worked, but here are all the things you would need:

To prevent some nasty accidents if the HU-to-Grom cable gets pulled or jerked, it is a good idea to secure it to one of the many handy wiring harnesses that litter the area. I used some cable ties that I had, you can also use twist-tie wire or tape, but cable ties are neat and easy to remove.

I decided to route the HU-to-Grom cable all the way to the left of the glove compartment gap. There is an A/C duct right under the glove box opening and I decided to double-sided-tape the Grom control box to that duct.

Here's the Grom control box double-sided-taped into place. The 3M tape isn't that strong, but the Grom box is very light, and should never be under mechanical stress anyway.

And another view:

You must ensure that the Grom control box clears the glove box when it closes. My first attempt failed (the edge of the glove box hit the Grom) so I had to waste another piece of 3M double-sided tape and relocated the control box a few millimeters.

You will also want to ensure that none of your cabling efforts block the cabin filter access panel, otherwise you'll have a heck of a time replacing the cabin filter later on.

There are two cables in the iPod/iPhone Adapter Kit: one from the OEM head unit to the Grom control box, and one from the control box to your iPod. I've already noted in the prior photos how to secure the HU-to-adapter cable.

However you must also secure the cable from the adapter to the iPod, so that if the cable gets pulled, it won't pull against the jack on the Grom adapter (that would either detach the box, given the "great strength" of 3M double-sided tape, interrupt the connection, or damage the jack on the adapter).

After securing the cable, place the glove box back into position, and dangle the Grom-to-iPod cable into the glove box.

And voila (ignore the Ambi-Pur air freshener propeller). Total time spent, approximately thirty minutes (including taking photos for posterity). If I had to remove the center console, it would probably take a whole lot longer and with my luck, I'd break some clips on those plastic panels and cause rattles in the car.

Press the "CD" button on the head unit twice to connect to your new CD changer (which is actually the iPod). The steering wheel controls work to control volume and change tracks. The disk-selection buttons on the head unit serve to select one of the first five playlists in your iPod.

If the head unit displays "EX 1" then you can control the iPod directly via its screen, and switch tracks/change volume via the steering wheel controls. If you press disc up/down on the HU, the display changes to "EX 2.. 6" which selects one of the first five playlists that you defined in iTunes. In EX 2-6 modes, you can't control the iPod via its screen.

In all cases, the Grom adapter also keeps your iPod charged up (doesn't work for iPhone 4's due to different charging voltage requirements, I didn't check on the iPad either).

Our New Friend Tom

2011-07-04T12:09:00.003+08:00

Lalai and I bought a TomTom XXL 550, based solely on my good feelings (as opposed to say, Garmin, or Aigo, or Morbella, or some other less-well-known GPS manufacturer).

Well, my new friend Tom doesn't know where Marina Bay Sands is, among other things. Takes a long time to get a fix (it would be better if the GPS could be left on all the time, but the Li-Ion battery goes flat quite quickly).

I have not tried any of the other navigation solutions (instantly gravitated to TomTom thanks to my work-related stuff) so I wonder if they're any better. Seems hard to imagine though..

ElasticFox on Firefox 4.01

2011-05-17T02:45:00.002+08:00

I've been using Amazon's great ElasticFox browser plugin for managing my Amazon EC2 instances. I've often had the need to manage 200 or so virtual machines, and the standard web-based dashboard is both glacially slow and prone to crash my browser.

One problem is that ElasticFox which was last updated sometime in September 2010, is "not compatible" with Firefox 4.01. There is an extremely simple fix for this:

Open the XPI file (it's just a standard ZIP file), edit the install.rdf file (an XML text file) and replace the maxVersion from 4.0 to 5.0 - this allows it to install on Firefox 4.01.

And.. that's all there is to it.

Load-Testing an SMTP Server with Oracle ATS

2011-04-19T13:49:00.011+08:00

Most people aren't aware that Oracle has a strong Application Quality Management (AQM) solution which Gartner has placed in the Leaders Quadrant of their latest Magic Quadrant for Application Quality Management in January 2011.

Thomas Murphy, Director at Gartner, says ".. as we note Oracle has solid tools, because of the customer base a natural channel but the testing tools are hidden to the world. Some of Oracle’s testing story is associated with the core DB but the majority with the Enterprise Manager set of products."

A blurb directly from Oracle's web site: "Application Testing Suite (ATS) is a comprehensive, integrated testing solution that ensures the quality, scalability, and availability of your Web applications and Web Services."

ATS provides a familiar Eclipse-based IDE and record/playback model for test creation. Web-based applications, Oracle Forms, Siebel High Interactivity (HI), ADF/JSF, Adobe Flex, and SOA applications can all be tested with ATS.

Application Testing Suite is widely considered to be very easy to use yet very powerful, but there is a downside: the record/playback model does not work very well for non-interactive applications, such as socket-based applications. In this blog entry, I'm showing how trivially easy it is to write a module to load-test an SMTP (e-mail) server.

The first step is to launch OpenScript, the Eclipse-based test GUI. Once launched, create a new test script:

ATS allows us to choose what type of test (Functional, Load, or General) we want to create. For this exercise, we select a General Java Code Script.

ATS will then create the generic Java Code Script test harness, which contains three methods, Initialize, Run, and Finish. Notice that the Record button at the top is grayed out, as we cannot meaningfully do a browser navigation to automatically create the test. Also note the Tree View and Java Code tabs at the bottom left.

When we switch to Java Code, we can see the (stub) test harness. For simplicity, let's put the entire load test in the Run section.

In order to send an email, we need to use the JavaMail API. JavaMail also uses the Java Activation Framework (JAF), but thankfully JAF is part of Java SE 6, so we don't need to add it. However, we do need to download JavaMail and put mail.jar somewhere on the class path so that our load script can find it.

This is very easily done for our script: select the Script menu item, then Script Properties:

Click on Script Assets on the left-hand pane, then click the Add button and select the Jar File option. Browse to wherever you've saved mail.jar and we're done.

The stub test harness looks like this:

import oracle.oats.scripting.modules.basic.api.*;
import oracle.oats.scripting.modules.utilities.api.*;
import oracle.oats.scripting.modules.utilities.api.sql.*;
import oracle.oats.scripting.modules.utilities.api.xml.*;
import oracle.oats.scripting.modules.utilities.api.file.*;

public class script extends IteratingVUserScript {
@ScriptService oracle.oats.scripting.modules.utilities.api.UtilitiesService

utilities;

public void initialize() throws Exception {
}

/**
* Add code to be executed each iteration for this virtual user.
*/
public void run() throws Exception {
}

public void finish() throws Exception {
}
}

We have to import the appropriate class libraries at the top..

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

Then replace the entire Run section with one of our own (in this case, I've hard-coded all of the parameters, sender, recipient, SMTP server, and message body):

 public void run() throws Exception {

// put recipient here
String to = "orly@nova-N81Vp";

// and sender
String from = "atsloadtesting@localhost";

// host name of SMTP server
String host = "demoserver";

// Create properties, get Session
Properties props = new Properties();
props.put("mail.smtp.host", host);
props.put("mail.debug", "true");
javax.mail.Session session = javax.mail.Session.getInstance(props);

try {
// Instantiate a message
Message msg = new MimeMessage(session);

//Set message attributes
msg.setFrom(new InternetAddress(from));
InternetAddress[] address = {new InternetAddress(to)};
msg.setRecipients(Message.RecipientType.TO, address);
msg.setSubject("Test E-Mail through Java");
msg.setSentDate(new Date());

// Set message content
msg.setText("This is a test of sending a " +
"plain text e-mail through Java.\n" +
"Here is the second line.");

// Send the message
Transport.send(msg);
}
catch (MessagingException mex) {
// Prints all nested (chained) exceptions as well
mex.printStackTrace();
}

}

You can then press the Play button to check that the load test works (you'll want to log in to your mail account and check that an email was indeed delivered).

The usual ATS features such as Data Banks can also be used. Let's say we want to parameterize the e-mail Sender. The first step is to create a new Script Variable. To do this, switch back to Tree View, right-click on the Run section, then select Set Variable:

We are then presented with a dialog box asking us to name the Script Variable (note that Script Variables and Java variables are not the same thing!) and provide a value. We can put in a literal value, or interpolate data from an external data source via the Substitute Variable button (the small chain-like button at the right of the Value field):

When we click on Substitute Variable, we are given a choice of where to get this Script Variable's value; we select Add new Databank:

Data Banks can be either a JDBC data source, or a CSV file. For simplicity, we select the CSV file, click the Next button, and browse to the location of the CSV file.

Upon loading the CSV file, we can select which column will be interpolated into the Script Variable, then press Finish.

We're now back at the Set Variable dialog, with both Name and Value fields filled-in:

On our Tree View, we can see that the new variable has been added to the Run section, however it has been added to the end:

So we simply drag it to right after the GetNextDataBankRecord step:

When we switch back to Java Code, we can see that a couple new code lines have been added.

 public void run() throws Exception {

getDatabank("avitek").getNextDatabankRecord();
getVariables().set("sender", "{{db.avitek.Username}}",
Variables.Scope.GLOBAL);


// put recipient here
String to = "orly@nova-N81Vp";

// and sender
String from = "atsloadtesting@localhost";
      ...

We now want to put the "sender" Script Variable, into the Java String "from" -

  String from = (String)getVariables().get("sender");

And that's it! when we next iterate the Load Test (whether in OpenScript, or in Oracle Load Testing if we want to simulate tens or hundreds of users), the "from" variable will automatically cycle through our CSV Data Bank. Obviously, the same principle can be applied to the rest of the variables, such as the recipient, message body, and so on.

This procedure can be adopted to any protocol for which a Java library exists (and for those that don't, you can implement the protocol yourself in Java). For example, if you want to load-test a GSM Short Message Service Center (SMSC) that uses the Logica SMPP protocol, all you will need is the SMPP Java library from Logica (they also provide a sample Java client which you can cut-and-paste into OpenScript) and follow pretty much the exact same procedure we've just gone through.

Enabling JMX in JBoss AS 6 and JDK 6

2011-04-15T11:23:00.006+08:00

I'm trying to create a demo of VisualVM (a really neat BCI tool that now ships with Oracle's JDK 6) connecting to Red Hat's JBoss Application Server 6. The wrinkle is that there is some interaction with JBoss' LogManager when JMX is turned on. This results in a torrent of class not found exceptions when starting up the Application Server.

To quell these errors, the following lines have to be added to the run.conf:


# stuff for JMX
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.port=6789"
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.ssl=false"
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
JAVA_OPTS="$JAVA_OPTS -Djava.rmi.server.hostname=your.jboss.ip.address"
JAVA_OPTS="$JAVA_OPTS -Djboss.platform.mbeanserver"
JAVA_OPTS="$JAVA_OPTS -Djavax.management.builder.initial=org.jboss.system.server.jmx.MBeanServerBuilderImpl"

# there's an interaction between JDK 6 and JBoss LogManager when JMX is turned on..
JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.jboss.logmanager.LogManager"
JAVA_OPTS="$JAVA_OPTS -Dorg.jboss.logging.Logger.pluginClass=org.jboss.logging.logmanager.LoggerPluginImpl"
JBOSS_CLASSPATH="$JBOSS_CLASSPATH:/home/orly/sw/jboss-6.0.0.Final/lib/jboss-logmanager.jar"

Note that the above example turns off all authentication for JMX connections.. not something you'd want to do on a server that's on a public IP. But I am lazy.. in any case, if you're using Linux, you can use IPTables to restrict which IP's can connect to your JMX port.

DIY Guide Scope

2011-02-19T21:54:00.004+08:00

I noticed that even with a careful polar alignment, I was getting star trails at 336mm focal length and 30-second exposures. A better polar alignment would fix this, but my Vixen Great Polaris sags a bit due to differential load and the tripod hub flexing, so I can never be too sure of my polar alignment from night to night.

The answer obviously is to auto-guide. I used the ZS 70ED as the guiding tube a few nights ago, and got about 20 arc-seconds of peak-to-peak RA error, which is pretty OK except for a large spike once every worm cycle. The Great Polaris has a large drift in declination though:

Today I took apart the declination axis, cleaned it up and loosened it a bit, and lubricated it (with canola oil, since I didn't have any engine grease or white lithium).

I made this short (80mm focal length), fast (f/2.8) guide scope out of an old Mamiya medium-format lens to which I'd epoxied a 1.25" eyepiece holder. Here it is bolted to my William-Optics ZS 70ED, with a Meade DSI Pro camera.

Since I now have the dedicated guide-scope, I can put the DSLR on the ZS 70ED tube now.

William-Optics 0.8X Reducer/Flattener II

2011-02-14T02:45:00.007+08:00

I got this flattener sometime in September last year due to the amazing egg stars (field curvature) of my William-Optics Zenithstar 70ED small refractor. I haven't gotten around to making a before-and-after comparison until now.

Center (this is Rigel) without and with the flattener. The stars aren't perfectly round due to my imprecise polar alignment.

without flattener	with flattener

And the edge (not extreme edge)

without flattener	with flattener

Auto-Guiding for Poor Man

2011-01-09T17:12:00.005+08:00

I finally got around to modifying my Vixen DD-1 dual-axis stepper motor controller so that it can be driven by PhD (through the GPUSB-AH module from Shoestring Astronomy).

The modification of the Vixen controller was quite straightforward and only took twenty minutes with a soldering iron. I didn't even bother to trace the circuit, but copied the picture from the Shoestring web site (first link above).

I also have a Meade DSI Pro Monochrome (first generation) that I used for some DSO imaging a couple months ago for my astronomy coursework at Swinburne. The problem with the DSI Pro is the tiny chip (Sony ICX424AL) so the field of view is tiny as well.

Since I had a William-Optics field flattener/reducer, I decided that I'll use my Zenithstar 70ED (with the flattener) as the imaging scope, with a DSLR, and use the DSI as the guide camera. My challenge was finding a suitable guide scope ("suitable" meaning "cheap") and securely mount it parallel to the imaging scope.

Based on some suggestions from Stuart on the SingAstro forum, I decided to use a camera lens as the guide scope. As I didn't want to butcher any of my collectible screw-mount Takumars, I decided to butcher this:

A Mamiya-Sekor C 80mm f/2.8 standard lens for the Mamiya M645 SLR. I also took a cheap Meade barlow and cut off the 1.25" eyepiece holder with a Dremel and cutoff wheel (actually a Bosch RTX.. same banana). After judicious application of epoxy, I was able to cement the eyepiece holder to the back plate of the Mamiya lens.

Next step was how to secure the Franken-guider to my Vixen Great Polaris. I did a bit of butchering on the DSI filter drawer holder by drilling two holes in it, then screwing the holder to a piece of wood:

I then epoxied the small piece of wood, to a larger piece of wood and let the whole assembly dry overnight:

After some trimming.. note my ingenious use of a somewhat longer M6 bolt with a wing head, instead of the original M6 hex-socket bolt, to both secure the wooden guider holder, and the original Vixen MT-1 motor.

And with the Meade DSI re-attached, and camera lens screwed on:

I actually got this working before with a less-robust wood bracket, and it guides just fine, except in declination where there's a lot of backlash.

How to Uninstall Expired LauncherPro from Android Phone

2011-01-06T11:03:00.003+08:00

LauncherPro is an abomination of an Android application that expires itself after some time. In fairness to the developer, it pops up some nagware screens every now and then. However it then goes off the deep end into pure evil-ness:

Once expired, LP will not let you do anything except launch a browser and go to the LP web site to download the latest version. There are two bad things about this:

not everyone has a data connection (my phone line has no data plan); other folks went roaming and disabled their data plan. Imagine their surprise when they get off the plane in their home country and find that LauncherPro has bricked their phone.
in my case, Wi-Fi was turned off. LP is so incredibly bone-headed, it won't let you access phone settings to enable Wi-Fi!

Some folks suggest using ADB from the Android SDK to force-uninstall LP. However this didn't work for me, as the phone needs to be in Debug mode for ADB to work.

Guess what.. with LP hogging the home button, you can't go to Settings to turn on Debug mode.

I finally found a workable solution: download the latest LauncherPro APK (or hopefully any other APK). Connect your phone to your PC and mount the SD card. Copy the new APK to the top-level of the SD card and rename it to something short (like lp.apk).

Unmount the phone, then in the phone browser (which is the only thing LP lets you run), type the following in the URL bar:

file:///sdcard/lp.apk

(notice the three slashes)

This will force-launch the Installer application on the phone. Now on my phone, it was set to disallow non-Android Market apps from installing; since the APK is not off the Android Market, the phone popped up an error and offered to let me change the application setting. Which launches the Settings application.

The Settings application also allows you to uninstall applications.

Which finally allowed me to get rid of that misbegotten abomination LauncherPro.

On the other hand, if your phone was already configured to allow non-Android Market apps to install, you may not get the Settings up. In which case, allow the newer LP to install and hopefully the expiration bricking would go away.

Me, I've sworn off LauncherPro forever. Get ADW Launcher instead.

New (Old) Camera Gear

2010-12-27T16:06:00.002+08:00

I've been using the Pentax system for the past three years, and in all that time have been somewhat painfully aware of its shortcomings in the autofocus speed department. However, the Pentax advantages (weather sealing, in-body stabilization, lower cost) have been quite compelling compared to Canon or Nikon.

I've been able to buy (used) a Canon EOS 40D body, and the 100mm f/2.8 Macro Ultrasonic lens for very good prices in the past few days, though. And using them has confirmed that Canon autofocus is at least a generation ahead of the K20D. It's been said that the K-5 has much, much better AF than the K20D, but a K-5 would cost 50% more than I spent for both the Canon body and lens.

So here I am with my new (old) very small Canon system. Obviously, I can't afford to keep duplicate lenses, so I'll probably sell off my FA 50mm f/1.4 and D-FA 100mm f/2.8 Macro, and replace both with the DA 35mm f/2.8 Limited Macro. Of course nothing beats the f/1.4 aperture of the FA 50, but one can't have everything. And the Canon 50mm f/1.8 II is quite cheap. The DA 35mm is still a 1:1 macro (albeit with a very short MFD) and can be used as a general-purpose lens as well.

I still plan to keep the K20D for now, as I can't afford a weather-sealed Canon body. Maybe I'll replace my 16-45mm f/4 ED AL standard zoom with the 18-55mm f/3.5-5.6 WR kit lens (which is weather-resistant! and cheap!) or, get the DA 21mm Limited.

It seems obvious that Pentax strengths are in weather resistance, in-body stabilization, and Limited lenses. Outside these areas, Canon and Nikon have more coverage.

Stupid High ISO Tricks

2010-11-07T03:51:00.005+08:00

I've been wanting a new point-and-shoot digital camera for years now, as the Canon Ixus 700 (SD500) that Lalai bought almost six years ago, while still solid (and on its second battery), is quite slow and doesn't have a wide-enough zoom. However I've never managed to pony up the cash for a Canon S90, G11, or a Panasonic LX-3 (and now LX-5) because I'm cheap.

Fortuitously, I was able to exchange (many of) my Citibank rewards points for some Best Denki vouchers. Unfortunately there weren't nearly enough to buy an LX-5. Hah. In any case, being quite budget-constrained, I narrowed down my choices to the Sony DSC-W350 (which has a 24mm Carl Zeiss Vario-Tessar and a trick Sweep Panorama mode); the Canon Ixus 300HS (SD4000), spiritual successor to the six-year old Ixus 700; and the Casio Exilim Z550 and H5. I was drawn to the Casio's because of their trick "pan focus" or hyperfocal mode, which Ken Rockwell raved about years ago.

On to Best Denki.. unfortunately, both Casio's felt cheap; and pan focus trick mode or not, the shot-to-shot time was eye-poppingly horrendous (three-second lockups in between shots). Maybe my expectations are high because of the Pentax K20D (which is great.. but heavy as well).

There was only one Sony DSC-W350 left, and it wasn't red. And being the last one, it was a much-handled display unit. I tried the W380, which was similarly sluggish. The Canon SD4000, in spite of Canon's "high speed" moniker and its back-illuminated 10MP sensor, felt slow to hand as well. The nicer Sony's with the Exmor-R sensors were ought of my budget.

Now the Best Denki guy (whom normally I would pay no heed) showed me the Fujifilm F80EXR. What surprised the heck out of me was the zooming action: blazing-fast. Autofocus speed was pretty decent, too. And it had a glossy red metal case. It was just a bit too large for me. But it was cheaper than most of the alternatives. I had been reading a bit about the EXR sensor and Fujifilm's various tricks, so after an hour of back-and-forth (one of the benefits of a retail store, as opposed to reading reviews online!) I settled for the Fuji.

(Those vouchers were burning a hole in my pocket..)

After prolonged perusal of Kim Letkeman's blog (a fellow who seems to have made a career out of reviewing and critiquing the Fuji EXR cameras), I decided to use the 5MP hardware binned mode on the F80EXR. It's actually a bit of a step down from the Ixus 700's 7MP native mode (the F80EXR has a 12MP native mode, but it suffers from terrible noise reduction) but Kim said 5MP is all you need.

And the results.

A single, 1/6-second exposure at 27mm equivalent, f/3.3 (wide-open), ISO 800. Insanely stretched in Picasa. Lots of noise!

Using the F80EXR's trick low light mode, where it takes three shots and stacks them auto-magically:

Stupid comparison: Pentax K20D at ISO 800, f/4.0 (wide-open) with Pentax 16-45mm ED zoom set to 30mm, and a bit of stretching:

And the Pentax at ISO 3200:

For comparison, here's the SD500. Much tighter framing because the Ixus only has a 37mm lens. This image is actually cleaner than both from the F80EXR.. for these reasons: 1.0 second exposure (six times more than the F80EXR); ISO 400; f/2.8 lens; and a 1/1.8" CCD.

Unfortunately the image is ruined by shake, the SD500 doesn't have a mechanical image stabilizer which both the F80EXR and Pentax K20D have. I don't know how a modern Ixus with an image stabilizer would do in this case.

To compare, I took an image at 1.0 s, f/3.3, ISO 400 with the F80EXR. It's possible to hand-hold at 1.0 s (with a bit of bracing) due to the mechanical image stabilizer. Surprisingly, things are quite clean at this exposure, definitely better than our old Canon friend (as things should be!)

Overall, the F80EXR seems to be a half-decent choice: 10X zoom that starts at 27mm (a wider 24mm would be better.. but the Sony's and Casio's just didn't appeal to me; and the more-expensive Canon SD4000 starts at 28mm); have not tried the HD movie mode though. Zoom and AF are perceptibly faster than the half-decade old SD500; and the screen is nice and large.

At the end of the day, the most important factors for me are speed, a wide lens, and an image stabilizer. Am I unqualifiedly happy with this camera? not really. But for the price it has a feature set that's hard to beat. Would I choose it again? probably. Price is always the determining constraint.

Going Thirty-Five

2010-10-28T08:40:00.001+08:00

Yikes! I am thirty-five today.

Jupiter Again

2010-09-24T11:01:00.002+08:00

I caught Io transiting Jupiter a few days ago. This is with the Orion 100ED on Vixen Polaris, with Meade 126 Tele-Extender and Philips Toucam 740.

Poor Man's SkySensor 2000 Re-Engineered

2010-08-18T15:23:00.002+08:00

Lalai and I went to Punggai, Malaysia, last 7th - 9th August, with the SingAstro folks. The first day was a bust due to clouds, but the second day was quite OK. I just had a lot of problems with my Vixen Great Polaris with Autostar refit. The most annoying was the tendency of the Oldham couplers to slip, which caused loss of tracking. But the killer bug was the C9.25 OTA colliding with the motor bracket when pointed at Lyra (basically to the North-East, above a certain altitude).

Also, the Autostar hand pad was very unresponsive due to the well-documented wearing-out of the rubber keypad. These problems really got me thinking that I should be buying a Takahashi mount. Sure it's lots of money, but leisure time is valuable too and wasted doing field repairs. I guess I am a bit lucky; one of the folks who went to Punggai couldn't get his new Meade LS-6 working.

To avoid the mount collisions, I had to re-fabricate the brackets so that the motor doesn't stick out where the OTA can hit it. To do this, I had to use some pulleys. The problem with such a scheme is that the Meade DS motor shafts are not held in place by anything, they rely on being mounted straight-through to the couplers.

I found these "rod end bearings" from RS Online, which I'm using to fix the end of the motor shaft:

I used a 6mm bolt (with the head cut off) as replacement motor shaft. From left to right, the rod end bearing (self-aligning); timing belt pulley with two set-screws; and the Meade plastic gear.

Here's what it looks like on the motor:

I fabricated some new aluminum brackets for the motors, and screwed these brackets to plywood scrap.

Close-up of the RA axis:

and the DEC axis:

It ended up really easy to mount the rod end bearing to the aluminum plate, as the bearing had an M6 bolt as part of it; a simple wing-nut held it in place.

Construction Details: Meade DS Motors on Vixen Great Polaris

2010-07-15T22:01:00.002+08:00

I've written this documentation on how I mounted the Meade DS motors to my Vixen Great Polaris equatorial mount. My key constraint was that I do not have ready access to a variety of metal brackets, and I don't have much in the way of metal-working tools. All the metal-cutting for this project was done using a Dremel with a carbide cutoff wheel.

First: the dimensions of the Declination and Right Ascension mounting plates. These can be made of sheet aluminum of appropriate thickness, or, in my case, I used angle aluminum for extra stiffness.

Also, I re-did the Declination mounting plate by extending it opposite the motor so the plate would "grip" the dovetail saddle and be more secure against rotation, since it's secured by a single bolt.

Here is a detailed view of the Declination mounting plate:

The Declination mounting plate from the other side, showing how the motor is mounted (using ordinary bolts going through holes in the motor casing) and the 6mm shaft coupler. The DS motor shaft is more than 6mm in diameter, so I had to file it down a bit by chucking it in a drill and pressing a file against it while the drill was spinning.

Also, the shaft on the Great Polaris is slightly less than 6mm diameter, so I had to put in some flat tie-wire inside the coupler so that it wouldn't slip. Note that my couplers are friction-fit (the set-screw doesn't bear on the shaft but instead tightens down the entire coupler hole) and if you're using a set-screw coupler, you will not experience my troubles.

Here is the Right Ascension mounting plate. I had to put one-and-a-half thicknesses of 9mm plywood so that it was mounted just the right distance from the (original) RA motor mounting area, so that the DS motor's shaft aligned with the RA shaft. I got the half-thickness of plywood by splitting the plywood edgewise with a kitchen cleaver.

Another view of the Right Ascension mounting plate. I drilled a couple of holes in the Great Polaris itself in order to secure the plate. Since my GP is old and cost $200, I didn't feel too bad about putting two small holes in it.

Yet another view of the Right Ascension plate, showing the one-and-a-half thickness of 9mm plywood.

I used a plastic box that I found in an electronics shop to hold the connector panel. The box is screwed into my plywood 6" half-pier. The half-pier is needed because I live at a very low latitude (1 degree North) and the Vixen SX pier costs as much as my entire GP mount!

Jupiter Second Light

2010-07-12T02:55:00.003+08:00

Took more AVI's today. I think my previous processing was better (more detail on the disk, but also more blatant processing artifacts).

I took one AVI using the William-Optics refractor, one with the C9.25 at prime focus, and one with the C9.25 with the cheap Meade 3X Barlow.

Auto-Guiding with PhD

2010-07-11T22:02:00.004+08:00

I constructed a Meade 505 compatible serial cable so that I could upgrade the firmware on my Autostar 497 hand controller. The pinout for this cable can be found on Mike Weasner's Meade Autostar Information page. I'm reproducing the schematic diagram here:

The only challenge was wiring the RJ12 (4P4C) connector; I had to buy a crimper specifically for it. Most crimpers cost $20 to $30, but I found a really cheap one for $3.00 but it cannot crimp RJ45 connectors (it's purely for telephone cables).

The black dongle above is a Targus PA088E USB-to-serial converter; then a short RS-232 cable; and finally my home-made Meade 505 cable.

I got the ASCOM Platform files from ASCOM Standards, and the drivers for "Meade LX200 Classic and Autostar #494, #495, and #497 (combined telescope/focuser, 5.0.3)" from the scope drivers page on the same site.

Everything worked great out of the box, although it took PhD quite some time to connect to the Autostar (I thought it was hung).

I used the Philips Toucam as the guider; a bit of a challenge because it's not very sensitive and the sensor is so small. I used my William-Optics Zenithstar 70ED as the guide scope, and there was no payload. This scope is f/6.2 so if I use a 50mm f/1.8 standard lens as my guider, I should have less troubles with the sensitivity (or lack thereof) of the Toucam. The wider field of the 50mm lens on the tiny ICX098BQ sensor will also make life a lot easier.

I got an RMS of 0.36 (which I've read is pretty good) out of the box! and no major RA errors to be had. There was a persistent error in DEC that would take PhD some time to correct, I believe this is due to my lack of polar alignment, so I have to do a bit of tweaking.

Still, very good results! now I see why over-mounting is so important; the Zenithstar is rock-solid on the Great Polaris, even with the big imbalance (the standard counterweight is too heavy).

So now all that's left for me is to find some dark-sky site and good weather!

Jupiter First Light with the C9.25

2010-07-11T00:38:00.002+08:00

Last night was one of those rare nights where I could actually see Jupiter through the clouds. Of course most stars were completely invisible, but I'll take whatever I can get.

Here's the setup. I used a Philips Toucam webcam with my robotized Great Polaris, extra counterweights to balance the C9.25, and a jury-rigged (masking taped!) electric focuser. I was using QCFocus for focusing and capture, and Registax for stacking.

I had to add three 2.75-pound weights on the standard Vixen counterweight bar.

Here's a closer view of the extremely stone-age electric focuser; coupling the motor gear to the C9.25 focuser shaft was "implemented" with masking tape.

And the best image of Jupiter that I could get. This was at prime focus (no barlow lens) at f/10:

The morning after, I was able to improvise an extended counterweight bar, using a length of M16 threaded rod. With this extended shaft, I was able to dispense completely with the additional barbell weights. I'll buy one more and exercise my arms so as not to waste the weights.

I also improved the electric focuser with a mounting bracket that doesn't look like it came from a junk pile.

And here's the big scope and small scope. Our living room is a bigger nerd haven than Leonard and Sheldon's..

Poor Man's SkySensor 2000

2010-07-09T09:35:00.002+08:00

Here's the Orion Great Polaris (re-branded Vixen) which I got for USD 200 plus shipping:

It has the following modifications:

three 2.75-lb weights to balance a C9.25 (actually still a bit top-heavy, but the clutches hold..)
homemade 6-inch plywood half-pier
wooden tripod from a Vixen Polaris (I recycled the HAL-100 on the Polaris)
Meade DS motors
Meade Autostar 497 patched to unofficial firmware 43GF for equatorial mount support on non-LXD55/75 mounts

All told, the modifications added up to around another USD 150 (more than half of that amount was the Autostar 497, not shown) plus I used my trusty Makita router to make the half-pier.

Still haven't tested how accurate Go-To's are, but it seems to track well in RA (but all this trouble for RA tracking!) I also will be able to auto-guide because I constructed a Meade 505-compatible cable to do the firmware update.

Poor Man's Vixen Great Polaris

2010-07-06T01:25:00.003+08:00

In keeping with my "poor man" theme, I purchased a Vixen Great Polaris mount (without motors) for US $200 on ebay. This is a very low price for a GP mount; my Vixen Polaris is far too small to carry the Celestron C9.25 Schmidt-Cassegrain, so I needed something larger but didn't want to spend much money.

The GP I got (Orion-branded at that!) was cheap for a reason - it seemed to have been stored in somebody's garage for years. All the fasteners were frozen or rusted, and the polar scope was full of dirt. The worm gears were fine though, to my great surprise and delight.

I spent the past three weeks cleaning out the mount (still some rusty screws but those are just cosmetic), re-lubing it, and constructing another of my plywood half-pier specials.

My C9.25 (another ebay special) came with a Losmandy-style dovetail, and I didn't have a Vixen dovetail. The local astronomy dealer here in Singapore doesn't have a 17" Vixen dovetail either, so I'd have to order it again from the US and suffer another long wait.

Instead, I decided to make my own Vixen dovetail.

It's basically three strips of plywood epoxied together for strength (the laminated strips are stronger than a single plank of wood; besides I still had a lot of plywood left over from my latest dobsonian build). I screwed two stainless steel reinforcing straps from Daiso to each side of the plywood, where the Vixen saddle and retaining bolt hold on.

Primitive, but it works.. after a fashion.

Now this mount doesn't have any motors, and to go after Jupiter I need tracking. The Orion EQ-1M is on the Polaris (my grab-and-go, I just realized how much lighter it is after manhandling the Great Polaris plus C9.25 around) and I have some Meade motors lying around. I'll have to fabricate some brackets for the Meade motors sometime.

Poor Man's Half-Pier

2010-06-19T17:26:00.002+08:00

I've finally finished my Poor Man's Half-Pier. It's constructed solely from laminated layers of 9mm plywood and epoxy. A length of 10mm threaded rod from a store in King George's Avenue goes through the center of the plywood box, compressing the box between the EQ head and tripod hub.

And here are the results: with my modded Orion EQ-1M RA drive with 5.0 MHz crystal (it really needs a 5.12- or 5.185 MHz crystal for correct RA tracking rate).

Telescope Mount Hacking

2010-06-04T22:24:00.005+08:00

I purchased a Vixen Polaris mount off Astromart about a month ago. With my only past experience a lightweight Chinese equatorial mount, I knew that the Vixen would be a significant improvement.

I had to make a minor modification to the mount so that it can be used at very low latitudes, since Singapore is pretty much on the Equator.

My solution was to remove the existing metal pad which the latitude adjustment screw bore on, and placed a Teflon pad on the screw tip. I used a drill bit to ream out a cup-shaped divot on the Teflon pad. The latitude adjustment screw rests on this divot, and the pressure of the Vixen polar casing on the pad ensures that it doesn't fall off.

I still have to rig a half-pier (the real Vixen ones cost $200, more than I paid for the entire mount and tripod). This will allow enough clearance for the counterweight so the mount can be fully used close to the Equator.

Like many of these twenty-year old Vixen mounts, mine was missing the tripod leg spreader tray. I still had some spare 9mm plywood circles from my on-hold Dobsonian project, so I used that.

I also had an Orion EQ-1M quartz-controlled RA motor drive from the mini-EQ that I bought last year; I had given up on using this motor on the EQ-1 because that mount has a lot of backlash on its worm gear.

A few days ago I had the bright idea of trying to use the EQ-1M on the Vixen Polaris. I was expecting that an additional metal bracket or adapter would be needed to mount the Orion motor on the Polaris. But to my surprise, it bolted right up to an existing bolt on the Vixen housing:

Absolutely no mechanical changes were necessary to hook up the EQ-1M to the Polaris; however since there is no clutch, the RA slow-motion knob is unusable with the EQ-1M attached. Not a bad trade-off.

The EQ-1M tracked as designed: which, while better than no tracking, was not so great either. The Orion EQ-1 has a 100-tooth worm wheel, while all of the Vixen light and medium-weight mounts (Polaris, Super Polaris, Great Polaris) use 144-tooth mounts. This meant that the EQ-1M turned too slowly to track for more then 2-3 minutes at a time.

I decided to open up the EQ-1M hand box and see how to adjust the speed. I knew that the EQ-1M uses a stepper motor and was hoping there was some potentiometer inside the hand box that I could adjust to change the speed.

Opening up the hand box was quite straightforward. The first step was to pry off the caps on the key switches. After which I removed the two small screws that hold the 6V power plug on.

I then removed the four screws on the top cover; this allowed the top cover to be pried off quite easily. There was a daughter-board (or if we want to sound complicated, a "mezzanine board") screwed into the main circuit board on stand-offs. This daughter board held the key switches, and also had to be removed.

There were two integrated circuits on the main circuit board: a 74LS05 hex inverter, and an Atmel 89C2051-24 micro-controller. The Atmel had a 3.58MHz clock crystal. It was obvious that a dedicated stepper motor controller chip was not being used; instead, the Atmel was creating the stepping waveforms in software.

It immediately occurred to me that I could "speed up" the stepping waveform by making the CPU run faster. A quick check online showed that the Atmel is an Intel 8051-compatible chip, and can run at up to 24MHz.

The best-practice method of creating precise timing delays on an 8051 uses a countdown timer. Much like the 8253 in the original IBM PC! and crucially, the countdown timer decrements on every machine cycle, which is the main CPU clock, divided by 12.

So it was obvious that, assuming Orion used the best-practice for generating the waveforms, that the stepper frequency was directly related to the CPU clock, which is controlled by the 3.58MHz crystal.

Since the EQ-1M was designed for a 100-tooth worm gear, and the Vixen has a 144-tooth gear, the CPU would need to be sped up by 44% (144 / 100). This meant I would need a 5.15MHz crystal (3.58MHz x 1.44). No such crystal exists off-the-shelf, although Citizen (makers of the Eco-Drive watch, among other things..) has a 5.33MHz part. It's not generally available though (28-day lead time at Mouser) so I decided to go with a 5MHz crystal.

I had a very good experience with RS Online Singapore. I've purchased electronics parts from RS Philippines before, and they've always offered free delivery, but RS Philippines only takes bank deposits, and delivery takes a few days.

Anyway, I was able to buy a 5MHz crystal from RS Singapore; I put in the order at 2:00 a.m. and by 4:00 p.m. same day I had my crystals. I actually ordered six of them (5MHz, 6MHz, and 8MHz) because I wanted to try different speeds in case the 5MHz crystal didn't work out. Also the crystals cost $1 to $2 a pop, and I wasn't sure if RS would deliver a $2 part.

To replace the existing 3.58MHz crystal, the main circuit board had to be removed from the EQ-1M case. This required unscrewing three more small screws that went into the plastic. There were two machine bolts that held the stepper motor cable to the board; I removed these too but it turns out that step is un-necessary.

Un-soldering the existing crystal and attaching the 5MHz one was quite straightforward for anyone who's taken EE 12. The new crystal was much larger, so I had to bend it a bit so it wouldn't touch the keypad daughter board.

I also put a swatch of masking tape on the new crystal so it didn't short out any of the connectors on the underside of the daughter board.

Putting the handbox back together was straightforward; I decided against testing the EQ-1M dis-assembled, because taking it apart again would be quite easy anyway.

And the result: I had expected the mount to keep an object (Lunar crater) in the field for about 15 minutes at 215X, as opposed to 3 minutes un-modded, and 1 minute with no tracking. To my great surprise, the mount kept the Lunar crater in the FOV for much longer than I expected. I don't really know how long it could keep tracking, because I stopped timing after 40 minutes.

Overall, a great success!

And the end-result: my grab-and-go setup.

Do Not Buy!! Chinese RF-155 / F-155 O-Ring Flash Adapter

2010-03-07T23:33:00.005+08:00

Bought one of these gadgets at a store in Plaza Low Yat for 180 MYR ($54). There is a store in Singapore which sells these for much less, S$ 60 ($43). This is also sold in the rest of the world under the Phottix brand.

Now you may think this gadget looks very similar to the $300 Ray Flash, or the $200 Orbis Ring Flash adapter. Well, it does.. but it is far, far, far less efficient. I guess the factor-of-four price difference does count for something.. although honestly I don't see the value in a $300 ring flash adapter when you can buy a Sigma EM-140 DG ring flash for $380.

In my informal testing, you lose about six stops!!! of flash power. From 1/32 power at f/4.0 on my Pentax AF-360FGZ, I had to go to full power, and my target was still under-exposed. Of course the target was about 2 - 3 meters away, so if using this gadget for macro, then you'll have plenty of flash power.

But six stops of flash power loss is crippling. Overall, had I known how much light loss this thing has, I wouldn't have bought it, $50 price notwithstanding. I think there are LED ring lights out there that produce more light.

This guy reports only a two-stop power loss.

Catalyst 2900XL Pitfalls

2010-01-27T22:41:00.003+08:00

I got a Cisco Catalyst 2924XL-EN yesterday for S$ 100 (about US$ 70). This is for a software demo where I need the SPAN (switch port analyzer) functionality.

Because it's so old (IOS version 12.0.(5.2)-XU) and primitive, I discovered that.. first, the port mirroring setup page on Wikipedia doesn't give a working configuration. For old switches like these, it's a multi-step process, e.g.


#conf term
#interface fa0/1

#port monitor fa0/2
#port monitor fa0/3
#^Z

#wri mem

#show port monitor

to set up (and verify) that FastEthernet 0/1 is used to monitor interfaces 0/2 and 0/3. Far more than the two-line configuration in the Wikipedia page!!

Another important caveat is that Catalyst 2900 and 3500 switch ports are not auto-sensing MDI/MDI-X. To connect one of these switches to another switch, you actually need a cross-cable! how 1990's!!

I still haven't verified my SPAN port is working. Will do that tomorrow.

(Non) Retrofocal Photography

2009-11-18T01:48:00.002+08:00

I've heard on and on about the different "gestalt" of rangefinder photography: the non-retrofocal lenses, the finder where everything is in focus.. Ken Rockwell has ditched his Canon 5D and now proclaims the Leica M9 to be the best full-frame digital camera in the world, bar none.

Now if I had $9000 burning a hole in my pocket, an M9 might be vaguely of interest. I got to touch (!) and take a few shots with an M8.2 but I did not get what all the fuss was about.

A few days ago I was able to score a sweet deal on the ClubSnap buy and sell forums: a Kiev-4A Soviet rangefinder (the seller described it as a Kiev-IIA but I don't really care).

It cost all of S$ 50, not including the MRT ride to Novena station, and came with the Jupiter-8, a Russian copy of the 50mm f/2 Sonnar. I've had my share of shoddy Communist workmanship (an old Praktica MTL-5) but for S$ 50 I could hardly complain.

Slow shutter speeds are way off, seller's description notwithstanding: I calculate about two stops too slow. Which is not a huge deal, I'm not going to be hand-holding this at 1/10 or 1/25 anyway. Rangefinder seemed properly calibrated, and the minimal fungus on the lens was far less than on lenses I've successfully rehabilitated from the 'bay.

The seller kindly included a roll of Fuji film, so after picking the antique up I walked around near the Esplanade and took some pictures. Most of them were way off. The Kiev-4A has no meter, and with ISO 200 film you should be using f/16 and 1/200, but I foolishly combined the "sunny f/11 variation" and used 1/125 second since there is no 1/200 speed. Still, C-41 is quite forgiving so all my shots turned out usable.

Usable, but appallingly pedestrian:

I see no rangefinder magic, or Zeiss magic. Then again I have a bunch of Zeiss SLR lenses and see no magic. Still, having a completely meter-less, antique camera has proved amusing.

I should get my Fujica ST-605N (another meter-less relic) and Pentax P3 next time I go back to Manila.. for the complete retro experience.

DIY Audio Again

2009-11-03T08:57:00.002+08:00

I finally got the Wima capacitors from 8audio in Hong Kong. After soldering these to the TA2024 amplifier PCB (and adding a S$ 24 power adapter and some really old Aiwa speakers I got on ebay.com.sg) I now have sound!

The Tripath TA2024 is considered to be a very nice piece of audio gear, some people claim it's better than the GainClone (and all that for US $25 plus minimal shipping). And my DIY GainClone back in Manila sounds better than my Cambridge Audio amplifier, except for having a really ugly case, no volume control, and thumps on power-up and power-down.

I was really thinking of buying the Philips mini-component with a tube front-end, but it's gotten bad reviews and costs S$ 399 or thereabouts. Besides it's no secret that consumer electronic gear is as bad as the manufacturers can make it without pissing off customers. So for much less money (I did have to buy a power supply, soldering iron and a large roll of solder - they don't sell small quantities unlike at Alexan) I had half an hour of DIY fun and the knowledge that the amplifier I'm using is sonically superior to consumer gear that costs five times as much.

I can't really tell if this Tripath sounds fantastic because it's connected to cheap, used speakers (well S$ 3.75 for each two-way speaker is really cheap, so I had no expectations). Also the Nokia E51 is not a good audio source: there is audible hiss during low-volume passages. But then again I also heard hiss from Lalai's iPod Touch 3G during low-volume passages..

In any case (pun intended) all I need now is a good case for the amplifier, then I can go looking for Wharfedale Diamond 10's or something..

Finally Some Photos from the ZenithStar 70 ED

2009-08-31T00:42:00.002+08:00

I was able to order a "store demo" William Optics ZenithStar 70mm ED refractor from the W-O online store for $338. This included free shipping worldwide!

I had it shipped to Singapore and paid the 7% GST. At least no unpredictable customs fees depending on the phase of the moon and the arbitrary-ness of Philippines bureaucrats..

The thing has amazing fit and finish. The 10:1 2-inch Crayford focuser is really smooth, and yet does not suffer from creep. The entire focuser also rotates, although as reported by others on the internet, there is a "catch" at one point of the rotation which causes the 360-degree rotation to be not entirely smooth. Not a huge problem however as rotating the entire focuser is not something one does very often..

I also got an EQ-1M quartz-controlled motor drive for the EQ-1 mount which I bought at True Value. Actually I purchased an Orion mini-EQ mount and the motor for S$100 from someone on the SingAstro forum.

Here's an afocal Jupiter at about 140X (12mm Plossl, 3X Meade Barlow). It's not as good as it could be, I've seen much better with this type of equipment. The EQ-1 mount is really horrible, with a lot of backlash that needs to be taken up before the system starts tracking properly.

Also even with good equatorial alignment, the EQ-1M does not track perfectly. I would expect that Jupiter can only remain in the field at 140X (0.35-degree) for about 2 - 3 minutes.

And here's the moon, with 32mm Plossl and 3X barlow.

For The Birds

2009-08-09T12:38:00.003+08:00

Went to Jurong Bird Park yesterday (by myself, unfortunately).

I'd told myself I would try using my old Pentacon 135mm f/2.8 "bokeh monster" but manual focus just is so clunky. I ended up using the 100mm f/2.8 D-FA Macro, which, while a macro lens, works just fine, although it is a bit too short.

Big Bird:

Small Bird (lorikeet, about 4 inches long):

I think it's safe to say only a macro lens could take both these photos!

But that said, the K20D + 100mm Macro has got no chance at all of tracking birds in flight. And 100mm is too short for any except the biggest birds. So for captive birds the ideal lens would be a 70-200mm f/2.8 zoom. Which Pentax doesn't make, and the Tamron and Sigma offerings don't focus that quickly on Pentax bodies..

CMoy Headphone Amp

2009-06-29T01:04:00.003+08:00

I've decided to build a headphone amp (blame Dennis!) so that I can maximize my almost ten-year old Sennheiser HD495 phones.

Anyway Alexan doesn't have the OPA2134 but they do have the much worse (but still orders of magnitude better than the LM358!) TL072. About $1.50 apiece (67 pesos). Not so bad..

I use the "Gwado" design which is very similar to the CMoy but with lower gain and a series resistor to drive low-impedance cans. The Sennheiser is 32 ohms which is difficult to drive, more so with a lowly TL072. But, the TL072 is pin-compatible with the OPA2134, so if this is a success, I can get some of those and drop them in.

So far all I have is a protoboard layout. Because I don't have 3.5mm jacks, I can't pipe in a signal or pull out any output. All I can do so far is measure the DC offset. It's about 11mV on one channel, and 20mV on the other channel. Not small, but not fatal.

I'm using the virtual ground design with two 470uF capacitors, as in the original CMoy design. The clerk at Alexan failed to include any 0.1uF capacitors (which are power supply snubbers) and I didn't check. So I used some humongous 0.047uF, 600V (!) capacitors from one of my past photo-flash projects. These caps are even bigger than the 470uF electrolytics!

Once this build is validated, I will transfer it to an Alexan PC201 veroboard, which I've cut down to fit inside an HC101 plastic case.

Pentax A Mod

2009-06-27T02:16:00.003+08:00

Old Pentax manual-focus bayonet lenses are divided into K, M, and A types. The K and M only have mechanical aperture coupling, so on the "crippled KAF2" or "crippled KAF3" mounts, which are the mounts of modern Pentax SLR's and DSLR's, K and M lenses won't meter except in stop-down mode.

"A" lenses have a pattern of contacts on their bayonet which communicate their maximum aperture, which allows full program operation, P-TTL flash mode, and so on (basically everything except autofocus).

There's a mod floating around which supposedly tricks the camera into thinking any lens mounted on it is an "A" lens. This is easy to do because "A" lenses have a recessed pin which pops out when the aperture ring is moved to the "A" position. The moving pin is called the "A" pin. So to dupe the Pentax DSLR into thinking any lens mounted on it, is an "A" lens, all we have to do is short the "A" pin on the camera mount.

Here's your typical crippled KAF3 mount:

The "A" pin is the semi-recessed one that is third in line from the left along the rank of pins next to the lens release button. It's distinctive because it's flat and recessed, unlike the rest of the pins which stick out and are round. We need to short this pin in order to "tell" the camera that the lens attached is an A lens.

After getting the metal bayonet off. Note that there's a very thin metal ring which must not be molested or removed; there is a thin wire soldered to this ring and that wire had better not get cut!

This is the metal bayonet, stuff a piece of aluminum foil into the "A" pin hole.

Another approach is to put a tiny aluminum foil "cap" on top of the "A" pin itself:

Put the metal bayonet back (don't force it if it doesn't go in nicely, the metal washer underneath must fit neatly in for the bayonet mount to go down nicely). Torque in the screws as if it were a tire, opposite screws at a time, finger-tight only.

This is what the mod looks like:

An ancient K-mount Vivitar 90mm macro:

And as we can see, the camera thinks it's an "A" lens!

Now for a few caveats: fixing the lens at "A" doesn't really do anything. P-TTL metering results in massive over-exposure. The camera thinks that the lens is an f/1.2 lens (the fastest K-mount built) because your SMC-K or SMC-M doesn't have the aperture-setting pins, so program modes also result in massive metering errors.

Green button no longer works because the camera doesn't try to stop-down the lens anymore (it's an "A" lens, right?)

So the only benefit I can think of, is that aperture data is now recorded in the EXIF. But you have to make sure that your aperture set on the camera, matches the aperture ring on the lens. Also, since "A" lenses have a differently-designed diaphragm from K- and M-lenses, there will be exposure errors.

Overall, not a worthwhile mod but heck, it takes ten minutes.

Update: after a bit more testing, it seems that P-TTL flash does work, but only with wider lenses. I'll try to see if this mod is actually worth keeping, before I dismantle it.

Nikon DK-21M

2009-06-15T02:14:00.002+08:00

I fortuitously found a Nikon DK-21M eyepiece magnifier at Infomax in Market! Market! while looking for some computer parts. Which is a good thing because the computer-assembly exercise has turned out to be a disaster.

Anyway it was around $35 which is expensive as this is a sub-$30 item in the US, but one would have to deal with the hassle of shipping so it ends up about the same.

Here are three viewfinders: Canon EOS 350D, Pentax K20D without DK-21M, and K20D with the DK-21M. It's a usable magnification. Not quite a 5D-class viewfinder, but not too shabby.

Saturday Afternoon at the Manila American Cemetery and Memorial

2009-05-10T23:02:00.015+08:00

The Manila American Cemetery and Memorial is the largest cemetery in the Pacific for U.S. personnel killed during World War II, with 17,206 graves, 3,744 of which are "known only to God." It is also the largest American military grave site outside the United States, with more personnel buried than any of the American memorials in France.

Pentax P3, 50mm SMC-A, Konica Centuria 100 film

It is located in Fort Bonifacio, and I have driven past it literally thousands of times, not realizing it was there.

The headstones are made of marble which are aligned in eleven plots forming a circular pattern. Each plot has a alphabetic marker, to ease finding a particular grave.

Pentax K20D, 16-45mm SMC-DA

Pentax K20D, 200mm SMC-M

Pentax P3, 16-45mm SMC-DA, Konica Centuria 100 film

Pentax K20D, 16-45mm SMC-DA with circular polarizer

The chapel, a tall stone structure with a sculpture on its front and religious mosaics inside, stands near the center of the cemetery. The memorial is eeriely quiet, the only sound being the distant traffic, muffled by the trees, and the bells of the chapel, which toll every hour.

Pentax K20D, 16-45mm SMC-DA with circular polarizer

In front of the chapel are two large hemicycles with rooms at each end.

Pentax K20D, 16-45mm SMC-DA with circular polarizer

On rectangular Trani limestone piers within the hemicycles are inscribed the names of 36,282 of the Missing, both American and Filipino, who gave their lives in the service of America and who rest in unknown graves.

Pentax P3, 50mm SMC-A, Konica Centuria 100 film

Pentax K20D, 100mm Vivitar Macro

The missing are from all the States of the Union, as well as five hundred-odd Filipinos, from the US Army, Navy, the Coast Guard, Marine Corps, Army Air Forces, and the Philippine Scouts.

Pentax P3, 50mm SMC-A, Konica Centuria 100 film

Pentax K20D, 16-45mm SMC-DA with circular polarizer

A rosette is fixed next to the name of a missing soldier when his body is found. It's sobering to see that more than sixty years after the end of the Pacific War, probably less than one percent of the names on the limestone have rosettes next to them.

Pentax K20D, 100mm Vivitar Macro

Carved in the floors of the hemicycles are the seals of the American states and its territories.

Pentax P3, 16-45mm SMC-DA, Konica Centuria 100 film

The Saturday I was at the Memorial, there were almost no people on the grounds, just a handful of Filipinos and one or two elderly American men, perhaps the comrades of the soldiers whose names are on the walls.

Pentax P3, 16-45mm SMC-DA, Konica Centuria 100 film

Pentax K20D, 100mm Vivitar Macro

Some of the names on the walls are outlined in gold, and have a star next to them: the Congressional Medal of Honor, the highest military award that the United States can confer. There is a whole story behind these gold letters:

Pentax K20D, 100mm Vivitar Macro

Willibald C. Bianchi was a twenty-seven year-old Captain in the Philippine Scouts from New Ulm, Minnesota.

On February 3, 1942, he was cited for the action that would earn him the Medal of Honor:

For conspicuous gallantry and intrepidity above and beyond the call of duty in action with the enemy on 3 February 1942, near Bagac, Province of Bataan, Philippine Islands. When the rifle platoon of another company was ordered to wipe out 2 strong enemy machinegun nests, 1st Lt. Bianchi voluntarily and of his own initiative, advanced with the platoon leading part of the men. When wounded early in the action by 2 bullets through the left hand, he did not stop for first aid but discarded his rifle and began firing a pistol. He located a machinegun nest and personally silenced it with grenades. When wounded the second time by 2 machinegun bullets through the chest muscles, 1st Lt. Bianchi climbed to the top of an American tank, manned its antiaircraft machinegun, and fired into strongly held enemy position until knocked completely off the tank by a third severe wound.

Captain Bianchi survived the Fall of Bataan and the Death March to Capas, Tarlac. On December 13, 1944, with the Americans closing in on Manila, he along with 1,600 other prisoners of war from Bilibid Prison were loaded onto the hell ship Oryoku Maru, which was sailing for Formosa and then Japan. On December 15, the Oryoku Maru was sunk by bombers from the USS Hornet while it lay at Subic Bay, Olongapo.

He survived this sinking, and was transferred to the smaller Enoura Maru at San Fernando, La Union. On January 9, 1945, the Enoura Maru was sunk by five 500-pound bombs from US Navy bombers, once again from the USS Hornet, while it lay at Kaohsiung Harbor, Taiwan. Captain Bianchi was one of the 250-odd men who were killed instantly in the bow cargo hold when one of the 500-pounders fell in. His body was probably one of those buried in a mass grave on the Kaohsiung harbor spit and re-interred in 1946 at the National Memorial Cemetery of the Pacific in Honolulu, Hawaii.

Pentax K20D, 100mm Vivitar Macro

That's a good deal of history for one afternoon! I actually went to the memorial to try out my RAW processing workflow. It's been instructive. Also, I will not use the 16-45mm on the P3 anymore, it is prone to way too much vignetting on the film body; I thought I could tolerate some vignetting to have a super-wide field of view, but I've changed my mind.

DIY Beauty Dish

2009-05-03T20:26:00.004+08:00

Ingredients:

One aluminum pie tin (about $1 at SM Department Store):

Mark the outline of your hot shoe flash head on the underside, I used a white board marker:

Cut an H-shaped slot in the pie tin using a Dremel with emery cutting wheel:

Bend the tin outward along the H-cuts (I also used a screwdriver to poke the two screw-holes):

Second ingredient: the lid from a KFC Bucket Meal (free if you eat the chicken!)

I taped a circular aluminum foil cutout to the KFC Bucket Meal lid, this bounces the light from the flash back toward the pie tin, and eliminates the hot spot in the center:

Bolt the KFC Bucket Meal lid to the pie tin (it's easy to poke holes in the plastic using a heated screwdriver or similar):

The metal tabs formed on the underside of the pie tin are for fastening the pie tin to the hot shoe flash. Make sure to cover everything with tape to avoid accidents and so as not to scratch your hot shoe flash. I used a very thick rubber band to hold everything together (logo optional):

Here's what it's supposed to look like:

Nice ring flash effect:

I don't have any post-worthy portrait photos with the DIY Beauty Dish yet, but here is a close-up photo with direct flash:

and with the DIY Beauty Dish. Note the groovy circular highlights in the lens, and the much softer shadows:

I also noticed that on human subjects, at portrait distances, the Beauty Dish produces far more interesting lighting than ceiling bounce, let alone direct flash. It doesn't have the shadows under the chin of ceiling bounce, and it works even when there is no ceiling! (or if the ceiling is too high or too dark).

Pentax K20D for K10D Users

2009-04-06T01:25:00.004+08:00

Lalai and I just got a Pentax K20D after selling off the K10D and some of my lens collection. Or more accurately, I sold off some of my lens collection and Lalai reaps the benefits of having a K20D. :-)

The big story with the K20D over the K10D (at least on paper) are the following:

14.6MP versus 10MP for the K10D
ISO 6400 with the new Samsung CMOS sensor, versus ISO 1600 with the Sony CCD in the K10D
Live View
AF micro-adjustment for up to twenty lenses

In my limited experience so far, the K20D is a mixed bag. It produces far larger files (larger than a 50% increase in pixel count would suggest), and the Live View, while clunky compared to say a Canon EOS 450D, is still quite valuable for critical manual focusing.

The AF adjustment is also quite useful as my most expensive Pentax lens (a 16-45mm f/4 ED AL, not saying much) needs a large amount of AF correction (+120 um on the K10D, +10 on the K20D).

The K20D is noticeably slower than the K10D. I suspect that Pentax did not upgrade the processor and the 50% higher pixel count is taking its toll. Although the most user-visible upgrade for me (aside from the Live View and higher ISO) is that auto white balance is far more competent than the K10D. I actually can leave the K20D on AWB all the time and it handles tungsten lighting (and even the residual yellow cast of my 50mm Super-Takumar) with aplomb.

The Downfall of Fungus

2009-04-05T20:32:00.003+08:00

I've had quite some success "rescuing" fungus-laden lenses from ebay as well as from local sellers. Some of my notable rescues include a $20 Carl Zeiss 50mm f/1.8 Pancolar (which regularly goes for five times the price I paid) and a $30 SMC Pentax-M 135mm f/3.5 medium telephoto.

My latest rescue is an SMC Pentax-M 200mm f/4 with significant fungus on the front glass. The photo from the ebay auction:

And after some ministrations with a rubber bulb (to get the front ring off) and liquid soap:

Great success! now I can sell off my 200mm f/4 Super-Multi-Coated Takumar (which is optically near-identical, but requires an M42-K converter) to recover my costs.

Wisdom Tooth Extraction

2009-03-28T11:34:00.002+08:00

I finally gritted my teeth and agreed to have my impacted wisdom tooth extracted. I've had a trauma of dentists since I was in kindergarten, when a surly dentist at the UP Infirmary pulled out both of my front incisors in one go because I wouldn't behave. Those were just milk teeth but without the benefit of anesthesia.

Since then I've always avoided going to the dentist which wreaked havoc on my teeth.

(panoramic X-ray image of the evil tooth; I just held up the X-ray to the light and took a photo with my cellphone camera, hence the visible background)

I've always heard how painful wisdom tooth extractions are so I kept putting it off. However this particular tooth caused the good tooth in front of it to develop caries in an area that can't be restored unless the impacted tooth was removed. And I can't afford to lose more teeth! with dental implants going for $2,000 a pop..

Anyway, all in that wisdom tooth took three hours of surgery, six ampoules of anesthetic, and a lot of painful cutting and re-sectioning.

And now, two days later, my face is still mis-shapen like a gourd.

More Cheap Telescope Upgrades

2009-03-11T00:03:00.002+08:00

I've replaced the aluminum tripod legs on my cheap Barska with some wooden legs I had from a previous project. I even spray-painted them orange several years ago so they look like Vixen tripod legs.

These are more stable than the aluminum legs (more stable and with better damping, than the collapsed aluminum tripod). As such, the eyepiece is in a convenient position for seated observation even when pointing close to the zenith.

I just used some 1/4"-20 bolts to attach the wooden legs to the EQ hub. The bolts which came with the Barska are too short for the wooden legs.

This is a full-frame (uncropped) image of the full moon. I used a 32mm Vixen Plossl (giving 28X magnification) and the Pentax K10D with 50mm f/2 manual focus lens, afocal projection:

I'll just tweak the leg mounting, find a reticle eyepiece so I can guide through the main tube and take photos of DSO's using a 200mm Super-Multi-Coated Takumar piggybacked to the scope. That way I can do 30-second to 2-minute exposures without a motor.

If results are promising, I'll buy an EQ-1M motor for the thing.

Fixing The Cheap Equatorial

2009-03-09T23:34:00.003+08:00

Today I went to the mall and bought some stuff to fix the cheap and shoddy EQ-1 clone which came with my $110 Barska 90060 department store telescope.

To summarise, the problems with the Barska were:

Too much slop in the worm gear; this caused an unacceptable level of backlash when operating the Right Ascension slow motion control knob.
The counterweight is too light to balance my Celestron Vixen 80mm f11 refractor tube, which caused severe problems when trying to use the EQ-1 clone with my (decent) telescope.
Needed to adapt the non-standard dovetail to my 80mm scope rings.

To fix the first item, I bought a cheap (168-peso, roughly $3.50) set of Allen hex wrenches. Actually there was a Stanley-branded one for $6.00 but I am a really cheap person.

I loosened the tiny Allen screw at the three o'clock position in the above photo, adjusted the brass bushing with a long-nosed pliers, and tightened it up again.

To fix the lack of counterweight mass, I bought four 1.25-pound barbell weights ($1.00 each). Turns out three are enough:

I just wrapped some cardboard around the counterweight shaft because the holes in the middle of the barbell weights are much larger diameter than the shaft; I then tightened a hose clamp to hold the weights in place. Primitive! but effective.

A whole stack of washers and two ordinary 1/4"-20 bolts was sufficient to bolt the tube rings to the non-standard dovetail. I did hack at the dovetail holes with a screwdriver last night to make them large enough to thread a 1/4" bolt through.

In action:

I didn't extend the tripod legs, which left me almost lying on the ground (the moon was at the zenith). This made for much better stability but is not usable in the long run; I think I'll try my wooden tripod legs and see how much better that is. Wooden tripod legs are long and don't collapse though. They would be a pain to put in the back of the car.

Tracking was very good even with my very approximate polar alignment, and I can finally put that rolled sheet metal 60mm Barska toy refractor behind me (might make a good guide scope though). But now I want an EQ-1M motor, so that I don't have to turn the Right Ascension knob manually anymore.

Cheap Equatorial Mount

2009-03-09T13:58:00.002+08:00

I've been seeing these Barska 90060 telescopes at True Value over the past couple months. They always sell out really quickly but yesterday Dennis spotted a pair at True Value in Shangri-La Mall. I asked him to reserve one for me, and bought it last night. Cost around $110. This is in contrast to $70 to $100 in the US, however not factoring in the hefty cost of shipping a 20-pound box to the Philippines.

I really was only after the mount (or more specifically, the equatorial head).

I did not have high expectations (these things have 200-arcsecond periodic error, a wobbly aluminum tripod, and a poor-quality telescope). I did not even intend to unpack the telescope, instead I planned to mount my 80mm Vixen refractor on the mount.

A few conclusions are in order:

The 100-tooth Right Ascension gear has a significant amount of slop;
However the biggest source of inaccuracy is slop in the worm gear caused by an improperly-tightened end bushing. I intend to adjust this when I can get an Allen wrench set.
It uses a non-standard dovetail, however the entire EQ head is made of some pot metal so I enlarged the dovetail bolt holes with a screwdriver so I could bolt my tube rings to it.
The Celestron/Vixen 80mm f11 is way too heavy for the tiny counterweight.

The view of the moon at 28X (with a 32mm Vixen Plossl) and 90X (with a 10mm) was razor-sharp, with only a tiny hint of CA on the limb. The equatorial mount works as advertised, allowing hassle-free tracking (so long as the tube isn't so unbalanced by the tiny counterweight), even with only an eyeball polar alignment.

Due to the really heavy Vixen OTA, I decided to give the telescope tube (a 60mm f11) which came with the Barska a try.

To my tremendous surprise, the cheap plastic focuser is a 1.25" one, not the usual 0.965" on cheap telescopes. So I was spared the indignity of using the supplied Huygenians and Symmetrical Ramsden (17th-century technology!) eyepieces with the kit.

The view of the moon is decidedly less impressive than with the Vixen (as expected). The cheap plastic focuser doesn't quite reach focus with the 32mm Vixen Plossl, but the 10mm works fine and I could see the Straight Wall quite well near the lunar limb.

The 5x24 finder which comes with the kit has a very small eye relief, tiny field of view, and is pretty useless (I used the hole in the mounting stalk to aim the main telescope tube). Good thing I intend to use a Telrad or Rigel Quick-Finder (I have one of each) with the Vixen tube.

In summary, the Barska 90060 is a piece of crap which should not be purchased by newbie star-gazers, who will gnash their teeth in frustration at the many limitations of this mount and telescope. But it's a relatively cheap entree into equatorial mount land, and with enough tuning up and tooling, I'm confident that I can make it competent enough.

Bizarre Book Bin

2009-02-12T02:23:00.001+08:00

Saw this in a Carrefour supermarket near Excelcomindo corporate offices in Jakarta:

First time I've heard of PowerBuilder and Ulead Photoimpact being of a religious nature!

Full Moon

2009-02-10T23:30:00.002+08:00

Six full-resolution 10MP shots, 1/200 second, f/8, 200mm f/4 Super-Multi-Coated Takumar, Pentax K10D. Stacked with Registax and cropped to show only the full moon.

It's Photo World Manila 2009!

2009-01-30T18:21:00.004+08:00

It's Photo World again. Already been there twice. Nothing jumps out at me; I can't afford the f/2.8 zooms, nobody's selling Pentax primes, the Canon 5D Mark II plus 24-105mm f/4 L kit lens costs a mind-boggling 180,000 pesos which is the down payment on a car or an apartment (or could buy you a ten-year old Honda Civic or half of a ten-year old BMW 3-series sedan).

I was looking for the Nikon DK-21M magnifying eyecup, so that my K10D viewfinder can feel "full-frame-ish," but nobody has it in stock. Nobody has those cheap 350-peso umbrella clamps either, they're only selling the 1,200-peso umbrella clamps. I should make the clamps myself from steel epoxy, save me a trip to Binondo.

June the used camera guy has a 105mm f/2.5 Nikkor-P in thoroughly beat-up condition for 4,500 pesos. Not a bad price (checked ebay completed auctions) but I'd hesitate to buy one in such a state for that price. He said he'd bring some Pentax lenses tomorrow (but he said that yesterday!)

Maybe I should just buy wireless triggers and return Dennis' ones. Those I'm sure I will use.

2009-01-24T23:14:00.003+08:00

A lot of folks have reported stunning results with using old (mostly Russian and Leitz Colorplan) projector lenses on their DSLR. For example "Abbazz" on the Manual Focus Lenses forum has gotten some pretty good results.

Eager to emulate these successes, I got one of these for $2.00 from ebay, it's a Francke & Heidecke Heidosmat 110mm f/2.8 made in Germany. F&H went on to become the Rollei company so this lens has a distinguished lineage.

After unscrewing the chrome barrel, I put a few layers of self-fusing butyl tape around the inner barrel, and friction-mounted a helical from an old unwanted 135/2.8 Hong Kong plastic lens..

After threading the helical back on the 135mm lens barrel (still sporting its M42 mount, but with the diaphragm etc. removed)

I can screw the chrome barrel back on (the whole thing rotates to focus, but it's surprisingly user-friendly).

The problem is, this is not a good lens. The OOF highlights are horrendously bad.. but still $2.00 (more like $20 with international shipping) isn't too bad a bargain..

Here are a couple of outdoor shots:

It does have that dreamy, "ethereal" quality you get from old optics. However, the OOF background highlights look terrible!

Games Games Games

2009-01-14T01:02:00.003+08:00

A couple of Bethesda games.

Oblivion, from 2006 (with a ton of mods: Ashara's Sirens and Tritons, Beautiful People, Cernasite Dragon Eyes, Corean Hair, Eyelashes for Vanilla Race, Hentai Gentleman's Eye Candy body, Corean hair, Corean eyelashes, Ren's Hair)

Fallout 3, from late 2008. Same game engine, but with two years' worth of technical improvements. Not much in the way of mods for Fallout 3 yet:

I must say, the V.A.T.S. "bullet time" system in Fallout 3 is quite an amusement. And blowing enemies' heads off or vaporizing them is also vastly amusing.

Under $100 Studio

2009-01-08T22:50:00.004+08:00

The Strobist blog is extremely popular, with over two million readers, and made famous the concept of manual flash, particularly with older portable flash units.

Most Strobist users, in addition to using their camera brand's dedicated flashes, also use older, less expensive flashes such as the Nikon SB28, Vivitar 283/285, Sunpak 383, and so forth.

But one source of ultra-cheap flashes has been neglected to date: pre-Sony, Minolta-dedicated TTL flashes. These flashes, for some reason, are sold much more cheaply than their Pentax, Canon, and Nikon equivalents.

For example, I got this Minolta 2800AF for $7.00 in "Bargain" condition at KEH. KEH, incidentally, provides a warranty on their used goods, so it's safer than buying on e-bay. KEH is also quite conservative in their ratings of used equipment, their "Bargain" is your typical ebay seller's "Mint Condition."

Actually I got five of the Minolta flashes, the one pictured here is the early, somewhat rare one where the two X's in the "Maxxum" logo are interlinked; Minolta had to modify their logo after the threat of a lawsuit from Exxon, the oil company, which claimed exclusive use of the interlinked X's.

The Minolta 2800AF is a GN 31 flash, with 35mm of coverage. Some of them come with a diffuser which increases the coverage to 28mm and lowers the GN to 28. It has no tilt or swivel, takes four AA batteries, has TTL dedication for old Minolta AF cameras such as the Maxxum 7000, and has a mere two manual power settings: 1/1 and 1/16.

Still, not bad for $7.00 in my opinion.

Some of the later Minolta flashes have the "iISO" or inverted ISO shoe. These (such as the Minolta 3200xi and newer) will not mount on a regular camera hot shoe. Avoid if possible.

The best thing about these old Minolta flashes is their low 3V trigger voltage, meaning no need for hacking tricks to lower the trigger voltage. Cactus wireless triggers work perfectly. You can even mount the 2800AF on a Pentax DSLR and it will fire at full or 1/16 power (depending on the setting at the back). The Minolta-dedicated pins are completely ignored by the Pentax body.

I used the ordinary Cactus v2 wireless triggers, some 350-peso (about $8.00) 30-inch shoot-through umbrellas from JT Photoworld, 700-peso ($15) tripods from CDR King, and I used hose clamps and plastic cable ties to attach the umbrellas to the tripods.

These cheap tripods are flimsy but they have QR plates! so it's very convenient to remove the entire flash, Cactus, and QR plate in one go.

Here's my sofa studio:

And some results (lens porn!)

A couple of "real" portraits:

Not bad for under $100 for everything! (including the wireless triggers but not counting the DSLR)

Ghetto Monolight, Part III

2008-12-11T18:42:00.005+08:00

Due to lack of correct non-polar capacitors, I've decided to revamp my inverter circuit for the Ghetto Monolight. Rather than muck around with scary analog stuff, I decided to drive the power transistor using the trusty ancient LM555 timer chip, my good friend since elementary school. This is the circuit I decided to use:

The driving frequency of roughly 120 Hz is not optimal, since the transformer is a 60 Hz variety, but I didn't have the right combination of resistors and capacitors to produce the right frequency.

In any case, the damn thing works. Not fantastically, but it works. Based on my informal tests, the bare bulb has a Guide Number of about 10 (meters, at ISO 100). Pitifully low, but that's bare bulb (spherical light pattern); it will certainly go up with reflectors.

A more crippling drawback, I measured the cycle time, it takes about 2 minutes to charge the 1100 uF flash capacitor to 270V which is the minimum necessary to fire the flash tube. That's unusably slow.

I'll try to use a bridge rectifier on the high-voltage output, this should halve the charging time because both half-cycles are used. I'll also get closer to 60 Hz for the inverter, and use a power MOSFET like an IRF530 instead of a BJT for switching the transformer (less voltage drop).

But even with all that, I don't expect charging time to go much below a minute. Still unusable.

I thought of this cheap but potentially lethal solution: drive the flash head (tube, capacitor, and dangly bits which trigger it) directly off the 220V line. That's how traditional studio equipment works.

By putting a light bulb (a.k.a. power resistor) in series with the rectifier diode, the current draw is limited to a reasonable amount. And still guarantee quick charging times. But it's scary: circuit failure equals maiming or death. Whereas by powering it off a battery, circuit failure just equals really nasty shock.

Ghetto Monolight, Part II

2008-12-09T23:02:00.002+08:00

Last night I built an inverter for my ghetto monolight. Tonight, I've put together a trigger circuit which produces the 4kV pulse to fire the U-shaped flash tube. I got the flash tube and trigger transformer from Electronics Goldmine. Here's a trigger circuit which I scrounged from somewhere off the intertubes:

Here's the completed construction, along with a 1100 uF, 350V capacitor from the broken Vivitar 283:

I also recycled the low-voltage trigger circuit that I constructed some months ago, and the hot shoe foot from the Vivitar. This allows me to fire the Ghetto Monolight from my Pentax K10D DSLR safely.

And here's the flash firing (photo taken with the Pentax K10D):

There's just one, huge problem. The one-transistor inverter circuit is unaccountably inefficient (it's supposed to be powerful enough to drive a 15W fluorescent tube, but this is not what I experienced). The bad news: it takes about a minute for the Ghetto Monolight to charge!

I need to build a more efficient, class-B inverter. But building a working flash is immensely confidence-building.

Ghetto Monolight, Part I

2008-12-09T00:36:00.003+08:00

My little experiment with the basket of teeny tiny flashes hasn't worked out. It's impossible to trigger all the flashes using a single trigger circuit (only one or two of the flashes fire). I don't feel motivated to assemble ten trigger circuits worth $3 each (and my labor) to fire tiny GN 7 flashes that cost $0.80 each.

What I've decided to do is use the trigger transformers and U-shaped flash tubes that I bought with the basket of tiny flashes, and make my own (full-power) monolights, using the huge capacitors from the non-working Vivitar 283 hot shoe flashes.

First step is to build a high-voltage power supply.

I used the "Super Simple Inverter" design from Sam's Strobe FAQ Components by Sam Goldwasser.

I made a few minor changes to the design: I substituted an MJE3055T for the 2N3055 in the design (TO-3 transistors are just so bulky).

And since Alexan Commercial was incredibly, out of 1 uF capacitors when I visited last week, I changed the timing circuit from a 1 uF / 4.7K combination, to a 2.2 uF / 2.2K combination. RC time constant is pretty much the same. I used the smallest 220V to 6-0-6 V transformer that Alexan had.

Prototyped it on a breadboard, got about 250V on the output of the transformer when powering it off a 6V gel cell, not too shabby:

I then built one copy on a piece of veroboard. I'll build the other one tomorrow night when I have more copious free time.

Next step, building the trigger circuit to produce the 4000V pulses to fire the flash. Coming soon!

The Quest for Better Bokeh

2008-12-08T01:20:00.012+08:00

Beginning lens "devotees" often mistake shallow depth of field for good bokeh. When I first used the Jupiter-9, I was bowled over by its "wonderful bokeh," as compared to, say, the Canon 50mm f/1.8 II or my cheap Canon zoom.

However, it turns out that "good" bokeh, particularly in the OOF highlights, is really hard to get: you want undercorrection of the background, so that the OOF highlights do not have hard edges. Erwin Puts of Leica fame claims that more highly-corrected (read: modern) lenses have harsher bokeh than "old" ones. Certainly, Veijo Vilva has gotten amazing results with an ancient meniscus Kodak VPK Anastigmat from the 1920's. But at the expense of flare galore and low contrast.

I decided to do a simple test on some lenses I have to while away the time.

First a couple of 50mm lenses: the Carl Zeiss Jena Pancolar, and the SMC-A Pentax.

	Pancolar	SMC-A Pentax
wide-open
at f/5.6

Both of them have slight bright-line bokeh wide-open, it's hard to choose between the two, and both have clean but six-sided OOF highlights when stopped down, due to their six-blade irises.

13 December 2008:I've added the 58mm f/2 Helios-44-2 (a Zeiss Biotar copy) which has an eight-bladed iris:

wide-open	at f/5.6

The Helios-44-2 also shows characteristic oval ("cat's eye") OOF highlights off-center when wide-open, and bright edges on the highlights. It cleans up and presents neutral bokeh when stopped down, but the edges on its eight-blade iris are still visible; it doesn't have as many blades as the Jupiter-9 or Jupiter-37AM. In other words, a perfectly serviceable but not noteworthy lens.

Now for two 135mm lenses, the Jupiter-37AM and the lens it was copied from, the Zeiss Sonnar:

	Jupiter-37AM	Sonnar 135
wide-open
at f/5.6

Both have very similar bokeh characteristics, as to be expected, as they are essentially the same lens. I think the Jupiter-37AM has better bokeh wide-open. Stopped down, both are clean, but the Jupiter comes out ahead (again) due to its circular iris.

Finally an unmatched pair, the "famous" Jupiter-9, and the SMC-Takumar 200mm f/4:

As confirmed by other reviewers, the Jupiter-9 has rather nasty bright-edge bokeh wide-open, cleaning up as it is stopped down. So much for being a "Sonnar copy," it certainly doesn't behave in the same way as the Jupiter-37AM.

	Jupiter-9	SMC-Takumar 200mm
wide-open
at f/5.6

The 200mm SMC-Takumar has fairly good bokeh both wide-open and stopped down, but as it has a six-bladed iris, the highlights are hexagonal when stopped down.

For now, I think the Jupiter-37AM is the best of the bunch.

Civil Disturbance

2008-11-26T19:50:00.003+08:00

I'm still stuck in Bangkok because opposition demonstrators have blocked the highway to the airport with their bodies and taken over the airport control tower. Haven't been away from the hotel because there has been a shooting and grenade incident in the city.

The Shangri-La Hotel is right on the banks of the Chao Phraya river, which is muddy but not at all smelly.

This is a "long tailed boat" as seen on Amazing Race Asia.

It's a car or truck engine (rear wheel drive) with the prop shaft actually living up to its name and extending into the water, with a propeller attached. The boat is steered by moving the entire (large) engine on gimbals.

Since the river isn't smelly, water taxis are actually practical.

Noodle Hottie

2008-11-26T00:27:00.003+08:00

It's Noodle Hottie!

You gotta love the people who thought up this imagery to sell instant noodles! sure beats Ate Shawie and her spiel about nutritious Lucky Me.

On the other hand.. anti-government protesters have overrun the Bangkok airport and all flights are cancelled.. so I don't know if I'll be able to go back home to Manila later today. Bad news!!

I've been in Bangkok since Sunday night for a couple of client engagements. I'm in the Shangri-La hotel which is right on the banks of the Chao Phraya river (it's the semi-circular building in the lower center of this Google Earth image):

Hotel driveway:

View from my room:

Boat terminal by night:

One of the boats plying the river:

Not So Good Ghetto Ring Flash

2008-11-13T00:06:00.002+08:00

Had a chance to work on my throwaway flashes from disposable cameras.

Learned a few things.

First, six disposable flashes in parallel draw a lot of current!

The flashes were charging up too slowly off a single 1.5V AA battery, so I decided to use a 6V gel cell I had lying around. Of course I had to somehow reduce the 6V to around 1.5V so that my flashes don't explode. My "solution" was six 1N4001 diodes in series; their forward voltage drop equals 4.2V, which brings down the gel cell's 6V to a safer 1.8V. Close enough.

What I noticed (the diode string is at the bottom-left of the picture) is that while the flashes were charging, smoke would emerge from the diode string! turns out the solder joints were melting!

To Dennis: now we know where the energy lost in the diode forward voltage drop goes. It becomes heat! lots of heat!

Bad news, I paralleled the triggers on all the flashes, and shorting it to ground only fired one of the flashes. I think the flashes have to be triggered separately.

Which means this article in DIY Photography, which so optimistically shows the flash triggers in parallel, is wrong.

OTOH, the article does mention you may need more than one slave. Oh well.

Cheap and Dirty Flashes

2008-11-07T18:43:00.002+08:00

I got eleven flash circuit boards from The Electronics Goldmine. They were on sale for $0.79 (79 cents, or PHP 38) each. I bought ten and got eleven.

Each one has a 160uF or 120uF photoflash capacitor, rated at 330V, a tiny inverter, and flash circuitry. It only needs a single 1.5V AA battery to operate. The process is simple: put the battery in, with positive facing the circuit board, depress the metal "diving board" switch on the PCB itself to charge up the capacitor, then short the two dangling wires to fire the flash.

Trivial! I think it's about Guide Number 6 to 8. Quite minimal, but people have made super cheap DIY ring flashes out of these babies.

For my purposes, I'll put five flashes into each ring flash (made from the bottom of a KFC plastic meal bucket). This will also give me two semi-powerful flashes for my ghetto studio.

First order of business was to remove the battery clips, permanently short the flash power switch, and wire the flashes together. I also have to parallel the trigger wires so that the five flashes can be fired simultaneously. So far I've only done the first two steps:

If I'm lucky, I'll get some results this weekend!

Советский объектив порно

2008-10-26T18:18:00.004+08:00

That's "Soviet lens porn" in the title, according to Google Language Tools.

Helios-44-2, 58mm f/2 Zeiss Biotar clone. This one was manufactured by Valdai, Valdai Optical-Mechanical Factory, located in Valdai (may be currently known as Valdayskaya), about 250 miles NW of Moscow.

Jupiter-37A, 135mm f/3.5 Zeiss Sonnar clone, single-coated. Manufactured by KOMZ, Kazan Optical-Mechanical Factory. Kazan is located about 435 miles due East of Moscow, in what was, or is, the Autonomous Republic of Tatars.

Jupiter-9, 85mm f/2 Zeiss Sonnar clone. This model manufactured by LZOS (Лыткаринский завод Оптического Стекла), Lytkarino Optical Glass Factory, based in Lytkarino, 100 kilometers north of Moscow.

Mir-1V, 37mm f/2.8 Zeiss Flektogon clone. This is the later, less valuable black MC version. Manufactured by Vologda Optical-Mechanical Factory. Located in Vologda, approximately 250 miles NE of Moscow.

All photos taken with a piece of tissue paper as flash diffuser for the built-in pop-up Pentax K10D flash, manual exposure, Carl Zeiss Jena 50mm f/1.8 Pancolar at around f/11.

Incidentally, "Jupiter" comes from the Greek Zeus, which sounded kinda like Zeiss. Creative, comrades!

Although, "Helios" is the Greek name for the Roman Apollo, god of the sun. The Zeiss Sonnar was such-named because it was very bright and fast for its day (which was the early 1930's). However the Helios-44-2 is not a Sonnar, the Jupiter-3 is.

Commodore Lives?!!

2008-10-25T22:01:00.001+08:00

Apparently, they do!

Commodore Gaming, complete with the age-old C-and-thingie logo.

I just logged on to EVE Online and was floored by the Commodore ad that appeared on the login screen. And my first thought was the title of this post.

Ghetto Studio

2008-10-12T16:28:00.004+08:00

Strobist has got nothing on me!

At least, in the ghetto, scraping-the-bottom-of-the-barrel area. Here's one setup (I have yet to get the other strobe working reliably):

Vivitar 283 with variable-power mod and low-voltage trigger protection circuit (3500 pesos, not so cheap, when all the shipping is factored in)
hose clamp
cheap tripod from CDR-King (750 pesos)
Cactus wireless trigger borrowed from Dennis
36-inch umbrella from JT Photoworld (400 pesos)
6V gel cell from Ace Hardware (500 pesos)

The Vivitar 283 out of the box has a pretty narrow light beam, not enough to cover the 36-inch umbrella. One has to use the XWA attachment to cover the entire umbrella; unluckily I only have one of these attachments so my other flash has the narrow beam. Useful as a hair light, maybe.

Result: one light only, and no backdrop or anything. It's amazing how sharp any lens is at f/9.5!

Which only goes to show, after you buy your DSLR and kit lens, buy a flash or two or three! Fancy f/2.8 lenses won't affect picture quality as much as good, controlled light. So in this regard the new Pentax K2000D with bundled external flash is actually a great move on Pentax's part. But I'm sure everyone will say "Pentax introduces a bottom-of-the-barrel DSLR at Photokina? they're sinking!!"

But the reality is a K2000D plus kit lens and kit flash will probably outperform a Canon EOS 5D Mark II with its kit lens in most cases where you can use flash.

Home Alone

2008-10-10T01:57:00.006+08:00

Lalai is off attending a Financial Services Summit being thrown by her employer in Hainan, China. Actually she left early Wednesday morning and will be back on Saturday afternoon.

Meanwhile, I get to stay at home by myself. It does get lonely and it's hard to sleep, so I while away the time with all my usual useless trivial pursuits.

I was digging in my camera and lens drawer (as I don't have a dry cabinet) and dug out my ancient Canon EOS 50 (Elan II) film body. It has no batteries but the last time I used it, it was very much alive. I popped open the back and found a roll of film inside!

Of course all of the film still outside the canister (maybe ten shots) got ruined, but I'm curious what's on the roll. Will have it developed.

Here's my latest (and last) acquisition: the somewhat-rare and somewhat-prized Carl Zeiss Jena 50mm f/1.8 Pancolar, this one's from the 1967 - 1971 era:

Photos taken with this, the Helios-44-2, another semi-famous normal lens:

I actually got the Pancolar for $30 plus shipping, didn't expect to win at that price because they normally go for much more. This one had fungus inside but a few minutes with rubbing alcohol fixed that. Fungus no more!

It focuses really close (to 0.35 meters), much closer than my other 50mm lenses (and I have lots of those). Well it's a Zeiss, a "zebra" model, single-coated, and the focus ring is somewhat gritty and not buttery.

The Pancolar is supposed to be fantastic but I haven't gotten to use it for much of anything. I actually can't say anything about it except I think it's sharper than my Pentax and Helios normal lenses. But not as sharp as the Rollei Planar.

It's funny, eight months ago, I actually wrote:

I guess I know what normal lens I want now; I can forget about the Zeiss Pancolar or the Helios-44. A 50mm f/1.4 lens on an APS-C DSLR is pretty much equivalent to a conventional 85mm portrait lens on 35mm.

Today, I have all the normal lenses I mentioned. Got them all for giveaway prices.

Evil Tow Trucks

2008-09-19T00:19:00.009+08:00

No, I don't have a photo of the evil tow truck.

But after my meetings with two clients, I decided to have a Starbucks. So I parked at Valero and went to get my coffee. This was around 6:00 p.m. already and everybody was parked on the street. Actually the slot directly behind mine was a no-parking zone, complete with rumble strips. In fact, scrawled on the asphalt was a message, "Toyota Corolla TRT-xxx pick up at Yakal St." So I knew it was a no-parking area.

Trouble was, the SUV in front of me was sticking about a foot into the rearward slot. So I had to park intruding a bit (about a foot..) into the no-parking area.

After I got my coffee, I went to Velazquez Park to play with my camera. Good thing I only took a half-dozen shots, because as I was walking back to the car, lo and behold here came the decrepit tow truck.

They stopped right beside me and the evil conniving opportunistic towing guy said bawal mag park diyan. To all my pointing out that the SUV in front of me was sticking out of his slot, the evil conniving opportunistic towing guy's answer was bawal mag park diyan. Hm.

His confederate had actually gotten out of the back of the car with his nylon tow rope. I was thinking what I could do to forestall them. My only not-so-bright idea was to get into the car, start the engine, and hold down the brakes so that if they tried to tow they would damage the car and I'd sue them.

All of a sudden, they decided to leave. Maybe the sight of me in a tie with an obvious DSLR around my neck gave them pause. It occurred to me later that, had they tried to tow the car, I would document everything: how the SUV stuck into my slot, how much I exceeded my "parking ration," the plate number of their decrepit tow truck, and all their mug shots, while all the time saying I'd see them in court. Because the truth is, they are opportunistic bastards who are not out to enforce the law, but to earn some ill-gotten gains.

Anyway I never had the chance to use my PJ skills because they left. When I was driving off, I saw them stopped about 200 meters down in front of Makati Sports Club attaching (or maybe, attacking) their tow rope to an old car.

Anyway, here's one photo from my five-minute walk in the park, with the Helios-44-2, stopped down to f/4:

Сравнивая 50mm Гелиос-44-2 на другие обычные линзы

2008-09-19T00:19:00.007+08:00

I recently got my hands on a nasty bargain: a 135mm f/3.5 Jupiter-37AM and a 58mm f/2 Helios-44-2 lens for the grand total of $9.00 (actually $17.12 including US shipping, and another 518 pesos for US-Philippines forwarding via Johnny Air Cargo "your friendly e-bay enabler!")

I must say the Helios-44-2 sets a new low in lows in the build quality department. Light years worse than the 1960's Pentax Takumars, significantly worse than my early 1980's East German Zeiss, measurably worse than my early 1990's Russian Jupiter-9 and Mir-1v. Seems after glasnost and perestroika the build quality of Russian lenses actually went up.

It's made of some grotty aluminum alloy (the filter ring was dented, when I tried to straighten it with some pliers, little aluminum bits fell off). The preset aperture mechanism wobbles perilously, the black paint is coming off, and it projects this air of mechanical cheapness. Kind of like a jeepney..

It does have that cool "Made in USSR" label though.

Anyway I just did some sample comparison images, these are by no means definitive.

Rollei 50mm f/1.8 Planar, Singapore, wide-open:

Pentax Super-Takumar 50mm f/1.4, stopped down to f/2 (and yellow cast bleached out with UV light):

Pentax SMC-A 50mm f/2:

Helios 44-2 58mm f/2:

In the sharpness department, the Super-Takumar beats them all, as it's already stopped down one stop while all the other lenses are wide open. It also doesn't have the "bright outline" bokeh that all the other lenses have, it does however betray its non-cool six-blade diaphragm in the OOF highlights.

In terms of overall image quality, I kind of like the Rollei (can't explain it), there's something about that Zeiss quality.. but it's ugly, I took the lens unit of the Planar and stuck it into the (plastic) focusing helical of a Fujinon 55mm f/2.2 which I destroyed, as Rollei SL35 lenses have too short a registration distance for K mount.

But the grotty Helios does show some of that creamy Zeiss bokeh (it is after all a clone of the Zeiss Biotar). Maybe I will always use it stopped down a bit (it has a super round diaphragm like the Jupiter-9 and Jupiter-37AM).

Here's the Frankenstein Rollei at f/2.8 with the Helios-44-2 (that 16-45mm f/4 ED AL makes a nice pedestal for the ancient lenses!)

Still very nice, circular OOF highlights, creamy bokeh.. I think I'm gonna like the Helios-44-2, it's like a shorter Jupiter-9.

Worship

2008-09-18T21:07:00.002+08:00

I was at Atrium Makati this afternoon to get an affidavit notarized. I seem to have misplaced my driver's license and one of the requirements to get a new one is an affidavit of loss.

Atrium is more notable because it's the national HQ of the PAG-IBIG Fund, which dispenses housing loans (Lalai and I are one of their millions of debtors). I was amazed and surprised that a government entity such as PAG-IBIG actually is useful, helped us pay for our house... but I digress.

Topic for today: for the first time I noticed a large (maybe four feet tall) statue of the Virgin Mary in the lobby of Atrium. The statue was on a pedestal so its head was like eight feet off the ground.

What I found slightly strange was that there was a woman there this afternoon who was all but clinging to the statue while mouthing some wordless devotion. Prayer for a foreclosed house? I don't know.. but there are a lot of foreclosures going on.

A month ago when I submitted two years' worth of postdated checks to PAG-IBIG, the man next to me was pleading for his house to the loan officer as it had been repossessed.

I just found the prayerful gesture a bit.. scary actually.

The Blue Light II

2008-09-16T15:21:00.003+08:00

Last month, I tried to remove the yellow radiation-induced haze from my 50mm f/1.4 Pentax Super-Takumar using an incandescent bug zapper bulb.

That didn't work well at all.

But last weekend, I used a T5-mount fluorescent UV bulb for a money detector (PHP 200) plus an electronic ballast for it (another PHP 200) and.. after three days of UV, the lens is clear! (well, almost).

Details here.

Pentax 135mm Lens Comparison

2008-08-27T14:42:00.005+08:00

Got one of these for a pretty good price. It's not the famous M42-mount Pentax Super-Takumar 135mm f/2.5, but rather the downscale, made in Taiwan, Takumar (Bayonet) 135mm f/2.5. This lens is pretty downscale as Takumars go, being from the budget line. It has four elements in four groups, and was made from 1980 to 1988. Not a classic by any means.

As if I don't have enough 135mm lenses already: I have an excellent Pentax SMC-M 135mm f/3.5, a Carl Zeiss Jena 135mm f/3.5, a Pentax Auto-Takumar 135mm f/3.5, and a creepy plastic $2.00 Hanimex 135mm f/2.8 which is extremely bad. But the Takumar (Bayonet) is a K-mount, not an unhandy M42 mount, and is a stop faster than the SMC-M, so more light and shallower DOF.

But how does it stack up? here are the contenders:

I took some photos of our housing development's water tower, comparing it to the SMC-M. The color cast is different, as the Takumar (Bayonet) lenses did not have Pentax Super-Multi-Coating, but rather an ordinary multi-coating (they are not single-coated, a common rumor, but probably single-coated on the inner surfaces).

Anyway, the full frame:

And comparisons:

f/2.5	f/3.5 or f/4	f/8

The Takumar (Bayonet) shows some obvious CA wide-open but shapes up admirably at f/4. I cannot really say that the SMC-M (which has a great reputation) wide-open is really that much better than the Bayonet at f/4 (one stop down). At f/8 of course they're pretty much identical.

A good buy, if I may say so myself. That f/2.5 could prove handy sometimes.

Mike Johnston Is Back!

2008-08-21T19:24:00.004+08:00

And here's one of his latest writings: How To Stress A Camera Lens. I've been a huge fan of Mike's work at photo.net and at Luminous Landscape. I used to follow with bated breath his weekly column, The Sunday Morning Photographer.

Of course it helps that his taste in lenses hews closely to mine. The 50mm f/1.4 Super-Takumar is one of his all-time favorite lenses. It's heavenly!

He has a new review of the 35mm f/2.8 SMC-DA Macro, where he enthuses,

If you'd actually like to buy this lovely device, please link from here so we can rake in the profits. I'll go mad I'll be so awash in money. I'll buy a sailboat. O what heaven the sea....

That's not something you see in an everyday camera lens review!

Anyway, the lens they're all gushing about is $540. Cheaper than that 50-135mm f/2.8 DA* SDM I've been lusting after, but not by much. And it's still the price of a Russian 135mm f/2.8 Tair-11A and an East German 75mm f/1.4 Zeiss Biotar put together, with perhaps some room to spare.. or closer to home, the SMC-DA 35mm f/2.8 costs as much as a Leica Elmarit-R 180mm f/2.8 which will almost certainly appreciate in value over the years (and in the meantime will make a killer portrait lens).

Oh well. Mike is still great.

SCTEx

2008-08-17T20:47:00.003+08:00

Drove to Subic last Friday for a client presentation. Was the first time I've taken the Subic-Clark-Tarlac Expressway, which is indeed a modern motorway very much like those I've seen in China, HK, and Malaysia.

Of course it was a Friday during work hours, but entire expanses of the expressway were completely deserted (unlike, say, NLEX).

I also got to play with the GPS on my mobile phone, and discovered that at (moderate) speeds, the car's speedometer is within 2 km/h of the GPS reading.

I actually hit 150 km/h on SCTex (for a while, there are supposed to be radar speed traps). The underpowered MZR-Z6 was turning at around 4,500 rpm at that speed. A far cry from the 364 km/h posted maximum speed on SCTex (by a BMW X6, incidentally I saw one at Pacific Star last Thursday).

The Blue Light

2008-08-13T14:24:00.000+08:00

I have an excellent Pentax Super-Takumar 50mm f/1.4 normal lens from the late 1960's. I got it on e-bay for a relatively low price.

Just this morning, after reading an extremely informative thread on the Manual Focus Lenses forum, I was finally able to verify that, based on my lens' serial number of 37801, it is one of the earlier Super-Takumars with radioactive thorium glass in one of the high-index elements.

Turns out, the yellowing of these radioactive lenses is actually the reaction of the Canada balsam (a tree sap, used to cement lens elements together) when it gets bombarded by particles over a period of time.

Prolonged exposure to ultraviolet light actually bleaches the Canada balsam (UV light is well-known to fade dyes and other polymers), so the yellow cast disappears.

Here's a comparison of the Super-Takumar with an SMC Pentax-A, which shows the slight color cast of the Super-Tak:

Super-Tak:

SMC Pentax-A:

The Super-Tak has an obviously warmer cast (which lots of people like, incidentally..) but a histogram shows that it's only about half-a-stop faster than the SMC-Pentax (which is an f/2 lens), probably due to the yellow cast absorbing some light. I don't like my f/1.4 lens suddenly becoming an f/1.8 lens, so I decided to try to bleach the yellow cast out of it.

People supposedly expose their lenses to sunlight (which is rich in UV) for weeks or months at a time, but it's rainy (typhoon season) and besides I don't have a window which sees constant daylight. Also the lens would get wet as it rains in the afternoons (and I can't keep the lens behind the window, as window glass blocks UV).

Anyway, I went to Ace Hardware to look for a black light and found this:

It's an "Omni" brand bug zapper bulb, 25 watts and 220 V, quite cheap at 70 pesos (about $1.50). It's not quite a black light, as it's an incandescent (not surprising given its rock-bottom cost!), so it has really pitiful UV output. However, I think it's still better than sunlight:

The mean solar constant is 13.67 lumens/square centimeter. A 50mm f/1.4 lens has a front element that's 36mm in diameter, which gives an area of 1,000 square millimeters or 10 square centimeters. So if the Sun's rays are fully perpendicular to the front element, at most 137 lumens of solar energy goes into the glass, not all of which is UV of course.

My bug zapper bulb is 25 W, since it's an incandescent it's quite inefficient and would only put out about 8 lumens/W or 200 lumens. Only a small fraction of that is UV light. But I can make certain that this light is always going into the front element.

I put aluminum foil (shiny side down) over the front element of the lens, as I'll send the UV light in through the back. The discolored element is supposedly somewhere in the back.

I took a cardboard tube (actually an old piggybank that I got for exchange gift in Mozcom about five years ago) and lined the insides with aluminum foil, shiny side in:

By doing this, I'm hoping that a good fraction of the bug zapper bulb's luminous flux will end up inside the Super-Takumar, rather than being uselessly dissipated into free space.

And the piece de resistance:

It's The Blue Light!!!

(fortunately Hitler won't see this)

Update: 13 September 2008

What I didn't mention after I posted this is that the UV light from the incandescent bug zapper did not provide any more improvements to the color cast. That cheap bulb had just too little UV output to bleach the yellow-colored Canada balsam.

Last week though, while on one of the usual lunchtime Power Plant expeditions with Dennis, I found a fluorescent UV lamp at True Value. The shelf guy said it was used for money detectors and such. It was 6W and T-5 form factor. I figured that it would have about the same light output as a 30W incandescent bulb, but due to the more efficient UV emission of charged gas versus a hot tungsten filament, it would put out a lot more UV.

And I was not far wrong. After three nights of bathing under the relatively cool light of the UV fluorescent light (no electric fan cooling needed) the lens was obviously almost yellow-free.

Super-Tak:

SMC Pentax-A:

Super-Tak after UV treatment:

Actually the above photo is too blue (must be a white balance issue). But if it's blue, it's not yellow! (they're opposite)

Here's a photo taken with the Super-Tak after the UV treatment:

and compare with the output of the SMC Pentax-A 50/2 (a bit dimmer because I used the same shutter speed for both, and the Super Tak is an f/1.4 lens):

As Borat might say, Great Success!

Pacific Star Series

2008-08-09T22:52:00.003+08:00

These are a series of photos I've taken from the 19th floor of the Pacific Star Building in Makati.

Hidden enclave.

Hot air.

Republic of Makati.

Seedy hotels.

Gas station.

Laundry.

Taken with the Communist Kombinat Volkseigene Betrieb Carl Zeiss Jena 135mm f/3.5 Sonnar, and the Vologda Optical-Mechanical Factory Mir-1b 37mm f/2.8 (a Zeiss Flektogon clone).

A Walk in the Park

2008-08-08T23:20:00.005+08:00

Normally, I exit the office past 6:00 in the evening, but Lalai usually doesn't get off work till past 7:00 or 8:00 p.m. Since parking on the street in Makati is free after 5:00 p.m. I normally park the car in Salcedo Village (near the Peak Tower, where the Mozcom offices are) and take a nap.

Unfortunately it gets hot inside the car; I also don't want to leave the engine running because that sort of thing is hard on the engine and besides, gasoline is expensive.

This afternoon, while waiting for Lalai to be finished at work, instead of an uncomfortable nap, I went to Jaime C. Velazquez Park (where Ineng's Barbecue became famous, way before they had a store in Market! Market!)

Since I had my camera with me, I decided to amuse myself in the waning afternoon light.

Moon over Leviste Street (apologies to Sting).

Non-Working SD Reader & FaceBook

2008-08-08T12:10:00.003+08:00

I wanted to transfer some photos from my K10D to my notebook. I used to do this using the Tecra M6's onboard 5-in-1 card reader. But now I'm in Linux land, and, surprise, the "Texas Instruments PCIxx12 SDA Standard Compliant SD Host Controller" does not work. The tifm driver from Berlios won't compile either!

I tried using Pierre Ossman's sdhci driver (which did come with the Oracle Binary Image kernel) but it doesn't work.. in fact it hung my notebook good.. so much for Linux hardware advances. Although of course this is mostly TI's fault, as their SD controller chip doesn't have open specs (probably due to the DRM issues with Secure Digital and Memory Stick Magic Gate).

Out of sheer frustration (and boredom) I signed up for FaceBook. They certainly have a very slick interface. It's so much better than that old warhorse Friendster that it's not funny. The only drawback is the fancy FaceBook interface eats CPU; since my notebook has CPU throttling and fan control, when I'm on the FaceBook site the fan is always spinning up and creating noise like a tiny turbine.

Sub-pixel Anti-Aliasing on Linux

2008-08-07T17:55:00.003+08:00

After my accident with the Linux Oracle Binary Image last week, I've been using Linux exclusively on my notebook. It has been somewhat of a pain, but I'm surviving! (quite a feat, after two years of a Windows desktop). I even got the wireless working.

But something has always been bugging me about Linux: how to optimize the Cairo font-rendering engine to get really good anti-aliased text.

Now this may be old hat to the hardened Linux crowd, but it's a sufficiently major discovery for me.

First of all: what is the sub-pixel order? it turns out that the vast majority of LCD displays have RGB pixel order, which is why this is the default.

You can determine the sub-pixel order for your particular LCD by going to this: Lagom LCD test. Windows users don't have to do this, as they have the ClearType Tuning Wizard (not installed by default on XP, but you can get it from MSDN somewhere).

A second important note: (and I just learned this five minutes ago) do not enable full hinting! for some reason, full hinting make sub-pixel anti-aliased text look worse than regular full-pixel anti-aliased text. Although do note that on a CRT, full-pixel AA is the only game in town.

The Lagom site recommends to use "slight" or "medium" hinting. After I switched from full hinting to medium hinting, there was a huge improvement in visual clarity, it's so not funny.

Have fun with your LCD!

More German Antiquities

2008-08-06T21:04:00.005+08:00

I happened upon a Schneider-Kreuznach 135mm f/4.5 Xenar on the usual place when the auction was almost ending. Got it for $9.00 (plus the caveats about shipping).

According to this web page on the Schneider site, this lens was made sometime after November 1951, and before May 1952. A real antique!

It has a preset diaphragm, lots and lots of diaphragm blades (like the Russian lenses), and the (uncoated) front element is deeply set and so a hood is probably not needed.

It was in Exakta mount, but I did a temporary work-around by wrapping snippets of business card around the Exakta bayonet and then push-fitting an M42-Pentax K adapter ring over the business cards:

Wobbly, and it doesn't quite reach infinity focus.

From the performance of this lens, it is an uncoated triplet, very much like the Zeiss Triotar. It has low contrast wide-open, and is not as sharp as its East German sibling, the Zeiss Jena 135mm f/3.5 Sonnar.

Zeiss Sonnar	Schneider Xenar

Probably interesting for portraits and I'm eager to see its bokeh. I assume the bokeh is very nice, given the circular diaphragm opening.

I had some high hopes for "retro photography" with this lens, but bad luck reared its ugly head. While I was fiddling with it today, the front element fell out (my fault) and gained a large edge chip (a more accurate way of saying that is, "Orly unscrewed the front retaining ring, turned the lens over to look at something inside, and the front element fell on the floor and a piece of its edge got broken").

Technical me knows that such a chip (I even blackened it for good measure) has no effect on the photos, but that chip just reduced the lens' resale value by a huge amount. Not that I'm complaining, having gotten it for $9.00 - but it really was worth around $80 (I just got lucky on the bid), and I was hoping to build up a collection of antique lenses for future generations.

Adjusting Infinity Focus on the Pentax Super-Takumar 35mm f/3.5

2008-08-03T18:14:00.003+08:00

I have a Pentax Super-Takumar 35mm f/3.5 lens in M42 mount which I got some months ago. It has been sitting in my drawer all this time because on the 1.5X DSLR it's equivalent to a 52.5mm, which would be interesting except it's slow at f/3.5.

I suddenly got interested in it because of this thread on the MFLenses forum. One of the posters opined that this lens (along with the Mir-1b 37mm f/2.8 which I also have and which also just sits in a drawer) are some of the top wide-angle lenses.

Update: the Mir-1b, which won the Grand Prize at the 1958 Expo in Brussels, is actually a Russian clone of the Zeiss Flektogon.

So I decided to take some photos (out the window) with the Pentax, and quickly discovered that it doesn't focus to infinity. Here's a photo I took with the Super-Tak, the Mir-1b, and the SMC-Pentax DA 16-45mm f/4 ED AL:

The Mir-1b at f/2.8 was sharper, and so was the SMC-DA at f/4. Also it was obvious (from the split-image focusing screen as well as from focus confirm on the K10D) that the Super-Takumar was not properly focused at infinity. Apparently this is a common woe of wide-angle old Pentax lenses.

I found this blog post which details how to adjust infinity focus on a similar lens. The fellow used a sink drain plug to get the front ring off, but I didn't have such a drain plug, so I used a pair of pliers with rubber grips:

Everything else was exactly the same as in the original blog post. Took only about 20 minutes of fiddling to get the right adjustment.

Before and after (100% crop):

Much better!!

That said, I got to try the neglected Mir-1b and it's unexpectedly good! It's extremely flare-prone so I screwed a Pentax hood to the front, making it look quite impressive (almost like a small Canon 17-40mm f/4 L):

It also has pretty good ergonomics, and seemingly better bokeh than the Super-Takumar.

Mir-1b 37/2.8	Super-Takumar 35/3.5

Overstuffing The Bag

2008-08-01T14:18:00.002+08:00

Last month, after many brave declarations that "I am not a tourist," I finally bought a camera bag. It's a Lowepro Cirrus 140 and cost S$ 70 at the Changi terminal. Not exactly a cheap bag (I still have a giveaway Canon bag for my ancient EOS 3000N somewhere..)

The Cirrus 140 seems designed for a body and two lenses (and, when I get that fabled Pentax SMC-DA* 50-135mm f/2.8 it will fit) but I've managed to abuse the heck out of it.

On the left compartment: Carl Zeiss Jena 135mm f/3.5 Sonnar in M42 mount. On the right, LZOS/KMZ Jupiter-9 85mm f/2.0 Sonnar copy in M42 mount.

On top of the Zeiss: Pentax Super-Takumar 35mm f/3.5 in M42 mount. On top of the Jupiter, Pentax SMC-A 50mm f/2 in K mount.

Finally: Pentax K10D with mounted Pentax SMC-DA 16-45mm f/4 ED AL zoom.

And it all fits! just don't drop the bag, there isn't much cushioning effect left.

So that's four lenses plus the lens on the camera body. If I had a 50-135/2.8 it would consume the entire left compartment, so I would only be able to bring two more lenses (or one mid-length one like a 135mm).

200mm E-Bay Lens Comparison

2008-08-01T13:56:00.002+08:00

Pentax Takumar-A, 70-200mm f/4 one-touch zoom, 200mm f/5.6 (one stop down):

Sigma 70-210mm f/4-5.6 UC II manual focus two-touch zoom, 200mm f/5.6 (wide-open):

Focal brand 200mm f/3.5 M42 lens, f/5.6 (one stop down) -- this is the $1.00 lens with fine scratches on an inner element:

Hanimex brand 200mm f/3.5 M42 lens, f/5.6 (identical to the one above):

Surprisingly, the Takumar-A is still the best, aside from a somewhat warm cast. I had high hopes for the Sigma (but then I thought it was auto-focus, didn't read the description well enough) because it's two-touch: the Takumar-A is quite fiddly to use as its one-touch barrel is quite loose.

The Principle of Least Astonishment

2008-07-31T17:26:00.005+08:00

This morning I was playing with the Linux OBI (which is a desktop Linux distribution, based on Oracle Enterprise Linux 5.0, with all the drivers and everything for everyone's stock notebook). My employer actively encourages its minions to use the Linux OBI so that hopefully the tax we pay to malaria donors will go down.

The Windows installation on my 18 month-old notebook has been inexplicably slowing down in the past months anyway, and I already had a dual-boot Linux setup (albeit not the OBI, so the Intel wireless didn't work) so I thought I could "try out" the OBI on the existing Linux partition.

The OBI install is a stock Oracle Enterprise Linux 5.0 (based on CentOS 5.0 installer)... or so I thought.

In a clear and egregious violation of the Principle of Least Astonishment, the OBI installer downloads a kickstart file from somewhere in Global IT's guts and... partitions and formats your hard drive without asking any questions. No "will I use this existing Linux partition?" or anything like that...

It so happens I have almost two years worth of data on that 100GB notebook drive. Most of which I neglected to back up. Oops.

So I had to go running off to the mall to buy a 2.5-inch SATA drive case. And now I'm using some downloaded software off the net to image the notebook hard disk (on my desktop -- good thing I have a 500GB drive in this thing) so that afterwards I can try recovering the partitions and my precious files: off the image, to be safe.

How Bad Is The Hanimex?

2008-07-27T12:10:00.007+08:00

Compared my (badly) repaired Hong Kong Hanimex 135mm f/2.8 with the famous Pentax SMC-M 135mm f/3.5 at comparable apertures.

	f/2.8	f/4	f/5.6
Hanimex
Pentax

The original photo:

As expected, at f/2.8 it's pretty bad, getting better as I stop down. Of course the Pentax shows no image at f/2.8 so even a bad image is better than nothing. Peak performance is obtained at f/8, degrading due to diffraction at f/11.

The Pentax is better at all apertures except f/2.8 (obviously). It also exhibits higher contrast, almost certainly due to the better coatings. It did cost me $40 on ebay (as opposed to $1.00). However when factoring in the cost of shipping, the Pentax is "only" four times more expensive (about $60 versus $15). Is it worth it? of course. But sometimes you need the faster aperture.

$1.00 Lenses

2008-07-27T02:49:00.005+08:00

Sometimes my ebay adventures take a turn for the unexpected. A couple weeks ago I bid on an item with the following description:

Two Pentax screw mount M42 lens for repair, or parts.
Image 1:3.5 f=200mm Camera Lens. Has some scratches inside of glass.
Hanimex Automatic 135mm 1:2.8 Lens. Bottom pin is missing. It sounds like it is inside of lens, when you shake it.

I thought, "I don't have any f/2.8 135mm lenses, so might as well." I do have three f/3.5 135mm lenses though. I thought, the missing M42 stop-down pin was not a huge problem, since no modern DSLR can stop down an M42 lens anyway.

Got the lenses a couple days ago. Did I mention that I won the auction with a $2.00 bid? of course what with US shipping and forwarding to the Philippines, it ended up a bit more expensive than $2.00. Here's what I got:

The "Image" brand f/3.5 200mm lens is identical to my Hanimex which I got from Adorama for $20 or so, about four years ago. It's not a Komine lens because it only has six blades in the diaphragm. It has lots of fine scratches on what looks like the second element. They look like breakage, maybe in a cemented element. Not worth fixing, since the scratches are far from the nodal point, they won't affect image quality. Not that these dubious 3rd-party 1970's Japanese lenses were particularly great..

The diaphragm wasn't stopping down properly either, and the distance scale was off. A little disassembly and poking around fixed all of these issues and restored 100% functionality (except for the scratches on the glass, of course).

As for the 135mm.. it's a horrific piece of plastic work, made in Hong Kong. Hanimex really scraped the bottom of the barrel with this one. Green coating. Single-coated?

Almost everything about it is plastic. The reason the stop-down pin disappeared is that the shaft of the stop-down lever (inside the lens) was made of plastic and broke off. So the lever and pin fell into the guts of the lens.

What I did was to make a hole in the (plastic) inner barrel with a soldering iron. I then sacrificed one of the screws that held the M42 mount (mercifully, the mount is aluminum) to use as a shaft, as none of my screws were thin enough.

Dodgy, but it works (after a fashion). The screw was too long and the stop-down lever was wiggling, so I bent a bit of paper clip around the screw end to serve as a washer. Talk about a McGyver moment..

There even are instructions on how to disassemble and reassemble it!

Notice the mismatched screw. Had to use one I had lying around because I'd sacrificed the "real" screw to use as a shaft.

In total, after a couple hours' amusement, I got both my $1.00 lenses back to normal functionality. You may ask, why even bother, when the K10D can't stop them down anyway so it's useless functionality. Fixing these lenses is like climbing Mount Everest.. because they were damaged. And I could.

Wasn't dirt-cheap in the end because I paid some amount for the US-Philippines shipping. So not exactly $1.00 lenses after all is said and done. I got a redundant 200mm lens, and a 135mm f/2.8 (the extra stop over my existing f/3.5's may prove useful).

The 135mm is soft at f/2.8 (hardly unexpected!) but I have yet to compare it to the famous SMC Pentax-M 135mm f/3.5, because I couldn't stop it down before I finished repairing it. If it can match the Pentax at f/4, I will be (1) extremely amazed; (2) quite gratified. If not.. well it's a plastic Hong Kong Hanimex.

ALP Get-Together at PAGASA

2008-07-20T22:05:00.003+08:00

Lalai and I went to the Astronomical League of the Philippines get-together and photo opportunity today, Sunday afternoon, at the PAGASA observatory in UP Diliman.

It's been a while since we were back there, several years at least. The first time Lalai and I went there in 2003, we carried our ETX-60AT telescope in a backpack and took the bus. Something I wouldn't care to try these days..

Several of the members brought their telescopes to use as props for the photo opportunity.

One of the members brought his rebuilt 8" Discovery dobsonian telescope. He built the tube out of plywood and it has a very fine finish. Very much like the telescopes built by Normand Fullum (except without the fauns and fantastic carvings).

I'm very inspired to rebuild my 10" dobsonian (yet again) in this type of format. True, it doesn't break down well anymore, but at least it's solid and holds collimation well. It would take up the entire back seat of our car though, which is quite a negative.

PAGASA has been very much in the news recently because of the sinking of the Princess of the Stars ferry a month ago. The reprobate shipping company has been blaming PAGASA for not forecasting the weather correctly.

The PAGASA observatory seems to have a leaky roof, which explains the plastic water containers distributed over the floor of their building lobby. It's no surprise that PAGASA has shortcomings in the weather department, if they can't fix a leaky roof!

Heading Home

2008-07-17T04:36:00.002+08:00

Heading home after three days' worth of presentations at my employer's FY 09 ASEAN kickoff. Our fiscal year is around a month and a half old, so far.

It's been very busy, and the entire third day has been devoted to the vast new product offerings from the BEA acquisition (including some truly jaw-dropping list prices, at least for me).

In any case, I haven't had any time to go around (despite the Singapore Sale still being on, more or less: 32" Sony Bravia for the equivalent of 24,000 pesos) and my lugging my DSLR and three lenses has been pretty pointless. Still, some photos in the most pedestrian of places:

Self-portrait, elevator, Fairmont Hotel (we'd been barred from the usual Conrad or Ritz-Carlton for cost efficiency; also, our entire event was held at the adjoining Raffles City Convention Center).

Esplanade "Durian" and the Maybank building overlooking the Merlion by night. Well, the Durian and Maybank building are very small... I took this photo while walking along the street from Marina Square back to the hotel.

A different perspective on the Merlion, from my hotel room's balcony. Taken with a 200mm lens:

More Lens Testing

2008-07-05T17:09:00.004+08:00

I got another chance to test the accuracy of focus of the Chinese split-image focusing screen on my Pentax K10D. I had actually done a bit more correction and added an additional layer of sticky tape to the screen.

Original image:

The cropped portion is boxed in the center.

With Candidate #1:

and with Candidate #2:

Both images taken wide open (f/4), 1/1000 second, ISO 100, 200mm focal length.

Correcting Auto-Focus Errors on the Pentax K10D 1.30 Firmware

2008-06-17T11:44:00.009+08:00

I got the suitably-impressive sounding Pentax smc P-DA 16-45mm F4 wide-angle zoom from Francis from the DPP forum for half the local price (and I got free shipping, his cousin Louie carried it here from the US).

It's not as sharp, as weather-proof, or as luxurious as the Canon 17-40mm F4 L that I wrote about in March 2007 but at less than one-third the local price, I am hardly complaining!

The Pentax has the benefit of being slightly wider (25-70 mm equivalent). It has a "quick focus clutch mechanism" which is like a poor man's Ultrasonic Motor, focuses quite close, is decently sharp at F4.. I couldn't be more pleased.

What was less than pleasing was my discovery that it mis-focused a bit. I took a series of photos with autofocus and manual focus (checking with my Chinese split-image focusing screen) and I discovered that the manual focus shots were always, consistently, sharper:

Taken with auto-focus:

and with manual focus:

The amount of mis-focus seems disconcertingly large, but the above shots are at 100%. The actual area shown above are inside the yellow box in this photo:

So the amount of mis-focus is really not a killer; all digital SLR's have some degree of mis-focus; in fact Canon has an "AF shift compensation" menu in their flagship DSLR's (the ones which cost $5,000 to $8,000) so that you can dial in focus corrections for up to twenty lenses. Canon doesn't provide this feature in their lower-end DSLR's (anything that is not an EOS 1-something) because the lower-end models do not officially support split-image focusing screens, so lower-end users can't see in the viewfinder if their cameras are mis-focusing.

Pentax also has such a feature in their $1,000 K20D but only for up to five lenses if I'm not mistaken. The K10D, which is what I have, used to have this focus correction available in the debug menu, but in firmware version 1.11 Pentax disabled the debug menu.

Current firmware is 1.30 so there's no option at all for debug menu. What some people have done is downgrade to a hacked 1.10 firmware, apply the focus shift, then upgrade back to 1.30 afterward to get the Supersonic Drive Motor feature and ISO on the OK button. But it's a hassle.

Thanks however to the famous (or infamous) Pentax blogger RiceHigh, I learned about a Russian utility that enables debug mode on the 1.30 K10D firmware without any firmware downgrades: you simply connect your camera to your computer (which must have the Pentax Laboratory software and the Russian utility) via USB, run the utility software, and et voila, debug mode is enabled.

The trouble is, the debug mode utility was written by some Russians; and my copy of Windows doesn't have Cyrillic font support; and even if it did, I cannot read Russian. This is how the utility screen looks like:

I basically guessed which buttons to push to enable and disable the debug mode; I've numbered the screen so I can explain.

Firstly, you must connect the K10D to the computer (with Pentax drivers) with the supplied USB cable.

Second, always press button 1. Once this button is pressed, the radio buttons (UI elements 2, 3, and 5) become enabled.

Next, select radio button 5, to enable debug mode. To disable debug mode, select radio button 2.

Press button 3 to save your settings.

Press button 4 to exit.

It is necessary to power-cycle the K10D in order to get rid of debug mode (once you've disabled it via the utility).

When debug mode is enabled, disconnect the camera so that you can access the debug menu (press Menu, then select the Setup tab, then scroll to the bottom). The appropriate setting is the AF SHIFT setting.

I did some trial-and-error, and eventually settled on +120um focus correction; this gets the 16-45 AF to agree with the split screen (more or less) and gives relatively sharp photos.

And the final result:

Which is not bad at all! a little more correction (I also tried +160um and +240um) actually works better, but causes mis-focusing at other focusing distances, so the figure I chose was the best compromise I could work out in twenty minutes.

How Bad Is Bad?

2008-05-21T10:33:00.003+08:00

This is one of my favorite songs, "E-Bay" by Weird Al Yankovic:

The kind of stuff you'd throw away, I'll buy it on.. e-bay.

This is something which would probably fit Weird Al's description, a 28-90mm Quantaray (re-badged Sigma) zoom lens for Pentax AF. Got it for.. $7.00 plus shipping.

The question is, how bad can it possibly be? to find out, I compared it at equivalent focal lengths to two prime lenses which I have handy, a dodgy 28mm f/2.8 Chinon; and the well-regarded SMC-M 50mm f/2.0 Pentax.

This is the entire photo taken with the 28mm; the boxed area in the upper-middle of the image (the two microwave dishes) are the crops below.

And with the 50mm:

Conclusions? the $7.00 lens is not so bad, at small apertures and in the center of the image. Certainly both primes have more contrast and are faster, but they're not overwhelmingly superior. Still, I have some doubts about the accuracy of my manual-focusing (although both primes were at their infinity hard-stops).

I need a reference "known good lens" like a Canon L for comparison..

A Novel Cough Medication

2008-05-20T23:40:00.003+08:00

I've had a postnasal-drip induced cough for a month now. I've been to the doctor three times, at which times I've been prescribed a variety of anti-allergy medications. Trouble is, the cough itself degrades my quality of life. On my last visit yesterday, I was prescribed levodropropizine, which is a new non-opioid antitussive.

(All of the existing over-the-counter cough medication, including Robitussin, are opioid derivatives, which is why they are also popular with drug addicts)

The levodropropizine (Levopront) tastes weird, and is made in Indonesia. And I'm not so sure if it actually works. Thanks to Wikipedia, however, I've discovered a novel new method of suppressing cough: theobromine. A study at the Imperial College London shows that:

Theobromine inhibits sensory nerve activation and cough.

Usmani OS, Belvisi MG, Patel HJ, Crispino N, Birrell MA, Korbonits M, Korbonits D, Barnes PJ.

Department of Thoracic Medicine, National Heart and Lung Institute, Imperial College London, London, UK.

Cough is a common and protective reflex, but persistent coughing is debilitating and impairs quality of life. Antitussive treatment using opioids is limited by unacceptable side effects, and there is a great need for more effective remedies. The present study demonstrates that theobromine, a methylxanthine derivative present in cocoa, effectively inhibits citric acid-induced cough in guinea-pigs in vivo. Furthermore, in a randomized, double-blind, placebo-controlled study in man, theobromine suppresses capsaicin-induced cough with no adverse effects. We also demonstrate that theobromine directly inhibits capsaicin-induced sensory nerve depolarization of guinea-pig and human vagus nerve suggestive of an inhibitory effect on afferent nerve activation. These data indicate the actions of theobromine appear to be peripherally mediated. We conclude theobromine is a novel and promising treatment, which may form the basis for a new class of antitussive drugs.

This is very interesting because the most common source of theobromine is chocolate. You can kill a large dog by feeding it 400 grams of ordinary chocolate: canids are not able to metabolize theobromine as efficiently as humans, and that much theobromine will poison them.

Anyway, anywhere from 0.5 grams to 1.0 grams of theobromine is enough to obtain the good cough-suppressant effects. Unfortunately, this requires the ingestion of around 50 grams (an entire bar) of dark chocolate.

Lalai bought me a couple bars of 80% Lindt dark chocolate, which tastes terrible, I can't eat an entire bar of that. So I'm trying one-third of a bar, for now.

Raft of the Rowboat

2008-05-19T19:02:00.004+08:00

Yesterday I went downstairs to turn my boat upright. It had developed a crack on the railing because there was a concrete hollow block under that point. It was also half-filled with rain water, trash, and what-not.

Still, it has held up pretty well! in spite of having no fiberglass coating or anything, this thing is still salvageable (unlike, say, La Méduse).

Which, long before movies like Alive! and Hannibal captured the ewww factor of human hors d'oeuvres.

GSK >> Symantec

2008-05-19T18:58:00.003+08:00

The real antivirus:

Or, how GSK has managed to extract another $200 out of me. The net result of which I have to stay home for the next two weeks.

Good thing it's the end of the Fiscal Year. So us in pre-sales are really not doing a lot of work right now; and most of my work is remote anyway so even though I'm on leave, I can still stay in touch and do what work is required.

Friendster's Long Goodbye

2008-05-16T21:21:00.005+08:00

I once read a very interesting article of how Friendster, a "pioneer" in the social-networking business, frittered away their early lead and got their asses royally kicked by Myspace and Facebook.

Here is that article, How To Kill A Great Idea.

It has some thought-provoking points, such as: Friendster expended large amounts of CPU cycles and development effort in order to speed up the display of the front page. If you've done any networking-type application, you'll know that displaying the user's "network" is a rather CPU-intensive task that requires querying the database table which contains users.

The problem with this scheme is that people are continually updating that table as well (members being added, that sort of thing). So it's a very heavy read-intensive workload, but with significant write workload as well. Deadlock City!

In one of my previous careers, I worked on a local (Philippine) social networking site which was hosted at my employer. We encountered this exact problem. The site was using MySQL MyISAM table type, which as is well known sucks for concurrency. I spent an entire night converting that table to InnoDB (those were the days when InnoDB was the golden table type, not yet subsumed by Larry). After that.. performance was better.

Not much better, though, so I added caching of the user thumbnails. It stands to reason that when you display a user's network, you also want to display the egghead thumbnails and pa-cute teeny weeny portraits of their so-called friends. All this means that every time the front page is accessed, a ton of bricks falls on the database server.

Anyway, back to the story.. the article I've referenced mentions how Friendster tried to optimize this page-load problem; those of us who've been on Friendster forever (like me) and went through their JSP incarnation, then the PHP rewrite.. the relocation of parts of the dev team to the Philippines.. and the never-ending protests of users over the slow site.. will remember how slow Friendster was back then.

And the ironic thing is, one of the competitor sites dispensed totally with calculating a user's network on page load: turns out, a huge part of the cachet of these sites is looking through people's mug shots, regardless of whether you're connected to them or not.

So that competitor both (1) side-stepped the problem of calculating the network (and incidentally they also used memcached to cache those pesky thumbnails); and (2) gave users what they really wanted - the capability to browse through strangers' profiles without the limitations of only being able to see people on one's network.

As of 2007, Friendster is being kept alive by users in Malaysia, Indonesia, Singapore, and the Philippines. They have long been eclipsed in the US and Europe, and have sub-5% share. Which, I think, also explains why their site is usable now: there simply aren't that many users!

As a result of this lopsided ASEAN membership, Friendster has been doing some schemes, some smart (multilingual support!) but I did this on Alumni.net in 2000 (using Oracle, by the way); and some not-so-smart, in fact downright braindead.

Witness my Friendster front page from five minutes ago:

Holy crap! I thought. What are "take it take it" Ruffa and Gretchen Barretto doing there! This is localization gone insane!

Achromatography

2008-05-15T00:44:00.002+08:00

With the growing popularity of photography, digital in particular, there has been a proportionate rise in off-beat photography. The most famous example of this is Lomography.

Practitioners of this variant of photography generally use a clunky Russian camera called the Lomo; alternatively they may use the Holga (a Russian medium-format) or the Chinese Seagull TLR, a clone of the Mamiya C330 but with abysmal quality control.

Part of the cachet of Lomography and its ilk is the sometimes fantastical photos taken with a light-leaky camera that sports a single-element (or, in the case of the Seagull, a triplet, still primitive) lens, and expired film.

In the digital world, the company Lensbabies has become popular with their primitive bellows-mount lens. In both cases, the popularity is due to the low image quality, lack of sharpness and contrast, tons of flare, absurd levels of field curvature.. all of which lead to "artistic" effects.

Since I'm too cheap to buy a Lensbaby, I've often wondered what kind of photos one can take with a plastic magnifying glass from National Bookstore. However, my only magnifying glass has a very long focal length (over 200mm) and is unsuitable.

However, a quick rummage through my parts bin turned up a roughly 85mm focal length cemented doublet achromat from a Surplus Shed eyepiece kit. (I used to make eyepieces for my telescope.)

This particular achromat has a large edge chip and some discoloration of the cement. In other words, it's perfect for artsy-fartsy experimentation!

What I did is find some cardboard, wrap it around the lens, add tons of scotch tape, and press-fit the entire assembly onto a plastic body cap:

And the monstrosity, mounted on my camera:

The lens is about 30mm diameter, so what I have is ostensibly an 85mm f/2.8 camera lens! of course this one isn't going to send the Zeiss Contax 85mm f/2.8 Sonnar running..

Here's a quick photo taken with my cardboard-and-tape lens (wide-open, it has no diaphragm):

and compared to the 85mm f/2.0 Jupiter-9 (a Ukrainian Zeiss Sonnar clone) at f/2.8

Well.. the achromatic lens certainly has character! it's a complete PITA to focus though.

What I need to do is get my hands on a cheap manual-focus lens (even one with ruined optics), strip out the entire optical train, and mount the cemented doublet to the front. That way, I can focus normally and it can mount normally on the camera. If I start out with an M42 lens, I can even get stop-down.

Back-Focus Issues on Chinese Focusing Screens

2008-05-10T17:54:00.004+08:00

I ordered a Virtual Village focusing screen for my Canon EOS 350D, but it arrived after the Canon had been disabled; after I got a Pentax K10D, I used its stock focusing screen plus AF focus confirm for some time, but started to miss the split-image screen, so I ordered another Virtual Village screen, this time for Pentax.

Virtual Village makes relatively inexpensive split-image screens, compared to say the Haoda, focusingscreen.com, or Katz Eye screens. Inexpensive meaning around one-third to one-fourth the price.

However, the cheap Chinese screens are known for looking "dirty" and having focus issues.

Yesterday I tried using my K10D plus Pentax SMC-M 135mm f3.5 prime, compared to my office colleague's Canon EOS 400D plus 70-200mm f4.0 L IS zoom. Of course my prime cost $40 and the Canon zoom cost $1,000 plus, but I did not expect a huge disparity in the performance, after all a prime is a prime.

But there was a huge disparity: a photo taken with the Canon was visibly sharper even in small sizes. Since I've noticed that my split-image screen does not indicate in-focus condition at infinity with my 200mm prime, I figured that it might need some shims to correct for the back-focus condition.

I found some stickers, cut them thinly, and attached them to the upper edges of the screen (facing the pentaprism):

It does look messy, but the bits of sticker are actually not visible in the viewfinder.

I did some focus testing afterwards. Here's a focus test before adding the shim:

and after:

Could be just me, but the "in-focus" text does look a bit sharper with the shim in place, and the out-of-focus areas in front and behind the text are more symmetrical with the shim: without the shim, most of the in-focus areas are behind the "in-focus" text.

I also noted that the screen now correctly indicates in-focus condition at infinity with a 135mm and 200mm lens.

And now, to test the relative performance of my $12.95 Sears 70-210mm f4.0 zoom, against the highly-regarded Pentax SMC-M 135mm f3.5 prime. Here's the whole photo:

And 100% crops of the top-most microwave dish. With the zoom (wide-open):

with the prime (wide-open):

with the prime (at f/8):

The SMC-M prime doesn't give up a lot, wide-open, and it's a lot sharper than the zoom, which is to be expected.

Emergency Battery Charger

2008-05-04T04:19:00.002+08:00

I tried starting the fifteen year-old Mazda 626 yesterday.

First problem was, it would no longer unlock. The battery was so drained that the remote unlock mechanism wasn't working anymore. I'd installed that remote because the driver side lock is jammed and won't open with the car key anymore. But with the battery dead.. back to square one. What I did was unlock the trunk (the key still works on the trunk lock), push down the back seat, and crawl into the car.

With the battery dead, of course nothing worked.

Incidentally, I got the 2008-2009 comprehensive insurance for the Mazda3 from Club Direct, which is an RCBC subsidiary. They offer low prices (around 21,000 pesos total premium for the Mazda3), six months at zero interest (admittedly Peoples' General also offers the latter), and, if you apply for insurance coverage online, you get a free emergency toolkit.

That toolkit is noteworthy because it comes with jumper cables. I've never had "real" jumper cables in my life, the one time I had need for one, I used an old extension cord (which got pretty hot from the current while cranking). With the 626, I always relied on push starting if the battery was too weak.

However, yesterday, push starting would not have worked at all: if the battery was so drained that it could not power the remote locking, it certainly would not be able to power the fuel pump. Ah, the problems with these new-fangled electronic fuel injected cars..

Anyway, thanks to Club Direct, I had jumper cables, so I decided to try using the Mazda3 to start the 626. For some reason, even after hooking everything up and with the Mazda3 engine running to give extra juice.. the 626 would still not turn over. Just clicking noises from the starter. I left the Mazda3 running and connected for about twenty minutes, but apparently that wasn't enough to charge the battery.

I've also learned that the car alternator cannot recharge a flat battery, it's only really for topping off the charge. So I removed the battery, hauled it upstairs to our apartment, and jury-rigged this improvised battery charger:

I had the 12V, 2.5 ampere transformer from way back, I was using it to charge gel cells for my telescope. But for some reason the charger wasn't working anymore, turns out several of the 1N5401 diodes were busted. Since I didn't have any more of those diodes, I was forced to use my ultra-expensive MUR1520 power diodes to build the improvised charger. I put them on a proto-board so that I can re-use them for some other purposes.

I don't know how batteries are rated now, but I assume this one is 50 Ampere-Hours. Since my poor improvised charger can only put out around 2 amperes, it will take more than a day to complete the bulk charging (which is 80% of complete charge). The MUR1520's also get really hot, I've had to leave a fan running pointing at them because they are so damn expensive and I don't want them to burn up.

Lesson learned, if you're not going to drive a car for a long time, disconnect the battery! and I'm 100% sure that damnable remote and alarm system is what drained the battery; even at 50 mA continuous draw, it would drain about 1 Ampere-Hour per day. So after a month, your battery is effectively flat. And somehow I think that alarm consumes more than 50 mA..

More Cheap Lens Comparisons

2008-05-01T18:59:00.004+08:00

I've improved my "test methodology" slightly: I now am using flash! this allows me to use ISO 100 and a higher shutter speed; I now use 1/30 second with Shake Reduction turned off, on a tripod.

So here are comparisons of several different (cheap) Pentax bayonet lenses that I have, all at f/5.6 and in the center, at roughly-comparable focal lengths:

Sears 70-210/4.0 @ 70mm f/5.6:

Pentax SMC-F 35-70/3.5-4.5 @ 70mm f/5.6:

Sigma 28-90/3.5-5.6 @ 70mm f/5.6:

Pentax SMC-M 50/2 @ f/5.6:

Pentax SMC-M 135/3.5 @ f/5.6:

The 135mm seems to be the best, although I don't know if this is due to the increased image scale resulting in better perceived sharpness. The Sears is probably the worst, which is no surprise, given that it is a 3X constant-aperture zoom and is old.

The Sigma, surprisingly, seems to give better performance in the center than the Pentax-F 35-70, which is a well-regarded zoom. Even more amazing is that I got it for $7.00 on e-bay (or $16.50 with US shipping).

I must add, that I suspect the differences in sharpness all boil down to accurate focusing. It's tough to manual-focus some of these lenses due to the small image scale; the Pentax-F and Sigma, obviously, used auto-focus. The 135/3.5 is a dream to manual-focus because it has a very long focusing throw and really "snaps" into focus. The Sears has a very short focusing throw and is a one-touch zoom to boot, which makes focusing even harder.

I did all of these test shots on a tripod, with flash (to allow use of ISO 100), and at f/5.6 which is at least one stop down from wide-open, which means this performance ought to be indicative of "typical" usage.

Rock Throwers on C-5

2008-04-27T15:24:00.003+08:00

I've been hearing lots of horror stories about rock-throwers and road-spikers along C-5 in Makati and Taguig over the past half-decade or more. Some of the stories I've heard include: spiking the road with nails so that passing cars get their tires flattened; putting a large wooden beam in the middle of the road so that fast-moving cars dent their wheels and blow their tires; throwing rocks at passing cars; pretending to get hit by cars that pass by;

And the most creepy (and perhaps an urban legend): dropping a dead body onto a car from an overpass, then in connivance with some corrupt cops, claiming that the driver of the car hit and killed someone, and shaking lots of money out of the driver.

In the first case (tire-spiking, wooden beam, or rock-throwing) the motivation of the criminals and drug addicts behind these scams is to get the driver of the car to stop. Then they would converge on the car and robbery (at best) to murder (at worst) would probably happen.

Anyway, last night Lalai was coming home from the office (Saturday). And some men tried to flag her down, and when she didn't stop they threw what seems to me (from examining the damage) to be a chunk of concrete hollow block at her windshield. It missed, but impacted the rear passenger door arch.

Good thing Lalai had listened to all the C-5 horror stories I've told her over the years, because she told me she wanted to stop and look at the damage but remembered what I'd said.

Anyway, the dent is small but deep, and it's right at the crease of the metal so it cannot be repaired by paintless dent repair: a proper repair would have to remove the surrounding paint, apply automotive body filler, and repaint the area. Which will cost a lot of money and take a week. Conceivably, I could claim it on our insurance but we'll still pay the deductible and have no car for a week. I have to decide by tomorrow whether I'll make the insurance claim because the car's current insurance runs out on Friday.

My other option is to not have it repaired; it is unsightly but can be lived with. The paint was stripped down to the metal though, so I'd have to put some epoxy primer or something on the exposed metal to avoid corrosion. And if I do that, it will probably look ugly. So I ought to have it repaired, cough up the deductible, and also have the old car re-registered and repaired so we're not without a car.

It's things like these which completely piss me off about our rotten miserable country. And things are bound to get worse what with the skyrocketing price of fuel and rice. There may be riots in the streets before long, but even if not, petty and not-so-petty crime will certainly increase.

Building a Better Barndoor, Part II

2008-04-19T19:59:00.004+08:00

I glued the motor/gearbox board to the front of the existing barndoor mount (after removing the stepper motor and stepper motor control board).

Unfortunately, after re-testing, I found that the motor turns at around 1.28 RPM (45 - 47 seconds per rotation) using a 1.5V AA battery and a 1N5401 diode for dropping the voltage (the 1N4148 blew up, not beefy enough).

I was able to get another bolt, with around 33 TPI (threads per inch), as compared to the old bolt which had 20 TPI.

At 1 RPM and 20 TPI, the linear movement is 0.05 inches per minute. At 1.28 RPM and 33 TPI, linear movement is 0.039 inches per minute. There's quite a bit of error, but I'll see if the tracking is good enough for 30-second exposures.

I've verified that even with a worse-case load (200mm lens pointed directly over the motor drive), there is no slipping.

I also purchased a Slik Mini-Pro III tripod (with ball-head) for 1,100 pesos at Camerahaus. The 400-peso mini-tripod from KL didn't have enough holding torque on its tiny little ball. With a "real" ball head, things are much more secure.

Now the proof is in the photography.

Building a Better Barndoor

2008-04-18T22:20:00.008+08:00

I've been working on my shelved barndoor drive for astrophotography. By lightening the upper wooden part and using a ball head, I've actually gotten the darn thing to track the sky.

It's been cloudy these past few days due to Tropical Depression Ambo, but I got some photos last Sunday. This is a 100% crop of Mizar and Alcor, the famous naked-eye double star in the crook of the Big Dipper:

and here's how it should look like (from a planetarium program):

You can even see the Tycho catalog star in the photo from the Pentax! not to mention, Mizar (the brighter, and hence larger star) is also a double. The photo either hints at the companion, or my barndoor was just vibrating a lot and produced that protrusion at 7 o'clock on Mizar.

It's a 30-second exposure at ISO 100 (forgot to change the ISO after taking some flats) using a 135mm Pentax Auto-Takumar. Not bad! it's obvious, that Mizar and Alcor did not trail. True, they are not round, but this is at 100% zoom. At sane viewing resolutions, they are definitely round.

The problem with the floppy drive stepper motor I'm using in my barndoor is that, it has extremely feeble torque. As a result, half the time it doesn't turn properly and so I get star trails. So the barndoor only works half the time, which is pretty annoying!

But I've hit on a solution. I bought two of these:

It's a "3-speed crank axle gearbox set" made by Tamiya for small RC cars, catalog number 70093. It's very popular with the robotics set because it's fairly cheap ($5, but I got mine in Park Square 1 for 258 pesos, or almost $7 each). The gearbox can be built in a high-speed (16.6:1), medium-speed (58.2:1), and low-speed (203.7:1) gear ratio.

The small hobby motor that comes with the gearbox set is a Mabuchi FA-130, a 1.5V unit that can take up to 4.5V (I drove it from 12V for a while).

I built one gearbox with the 203.7:1 gear ratio..

and the other one with the 16.6:1 gear ratio..

and improvised a method to drive the second gearbox from the output shaft of the first gearbox (there was an unused gear that coincidentally fit the hex output drive shaft, and was compatible with the 38-tooth main crown gear on the input side of the gearbox).

The regular driving gear (which is put on the motor shaft) has 8 teeth; the unused gear has 12 teeth, so the drive ratio of the second gearbox is 11.07:1 instead of 16.6:1 with the original gear.

This means that the final drive ratio is 2255:1.

I noticed that when driving the motor with a single AA alkaline battery, the final output shaft turned at about 5 RPM, which is five times too fast for my barndoor. That damn Mabuchi is like a tiny turbine, according to the specs, it runs from 6990 to 9100 RPM. Makes sense, given the drive ratio of my improvised compound gearbox.

I tried dropping the voltage to the motor by 0.7 volts (by putting a 1N4148 diode in series with the 1.5V AA battery). I took a video of the final output shaft turning; it slowed down for a while when my fingers weren't tight on the AA battery, but one complete revolution took 1 minute and 6 seconds. If I hadn't botched the connection, I expect the time would be almost exactly a minute!

It's a very fortuitous coincidence. My only problem now is regulating that 1.5V, as alkaline batteries are notorious for having non-constant output voltage. I could use the 12V or 6V gel cells I have lying around, but that's a lot of voltage, which I'll have to bring down a great deal.

An additional benefit of that huge gear reduction ratio is that it produces an eye-popping amount of torque. I'm 100% certain that even when loaded with the barndoor, the motor's speed will not be reduced by any significant amount.

Mass Effect, Here I Come!

2008-04-18T03:05:00.001+08:00

It's a miracle! my modest system will be able to run the PC version of Mass Effect!

Now, no more need to pine after an XBox 360! Praise be Bioware!

Antique Lenses

2008-04-17T14:40:00.000+08:00

I started collecting lenses seven years ago. I sent $70-odd (and another $20 in Western Union fees) to a guy in the Czech Republic for a 135mm f3.5 Carl Zeiss Jena Sonnar. Which I still have (albeit slightly worse for wear). Since then my collection has grown, however I never got to use it much until I got a DSLR in late 2006.

Here's my list (in order of increasing focal length):

28mm f2.8 Soligor M42
28mm f2.8 Chinon K-mount (doesn't lock on the body)
35mm f3.5 Pentax Super-Takumar
37mm f2.8 Mir-1V
50mm f1.4 Pentax Super-Takumar
50mm f2.0 Pentax SMC-M
55mm f2.2 Fujinon
35-70mm f3.5-4.5 Pentax F
85mm f2.0 Jupiter-9
135mm f3.5 Carl Zeiss Jena Sonnar
135mm f3.5 Pentax Auto-Takumar
135mm f3.5 SMC-Pentax M
200mm f4.0 Hanimex

Since the destruction of my 50mm f1.8 Canon EF, I'm left with one Canon lens (the 18-55mm EF-S kit) and one non-functional Canon DSLR.