Posts about photography, contract bridge, astrophotography, astronomy, Java development, internet systems.

Working with a broken astronomy camera

Last year, I had some really bad luck with astrophotography.

I replaced my old laptop (Dell, Windows XP) and installed a new suite of tools to replace the somewhat ancient and unsupported camera software. At one point during my first “shakeout” evening (October 2014), the new software started spinning my telescope around the declination axis. It made at least two full loops (720°), wrapping the cables around the mount and stressing the camera case.

Afterward, the shutter was not working, or making noise. In my attempts to solve that problem in the dark, I dislodged a small optical window.

Back at home, I disassembled the camera, and found that I could move the optical window back into position, but it wasn’t held there firmly. Everything else seemed fine though. The shutter worked well, and the electronics all worked.

All of the equipment has been put away since then, over a year.

The time was coming to get back into the game. I knew I’d have several hours of work to update the software suite, not to mention Windows 10. The most delicate update was for the firmware in the keypad of my Mach1GTO telescope mount. I spent an hour and a half on that one update, following all of the procedures carefully. The rest took another few hours: TheSkyX, CCDStack, SbigControl, PEMPro, Skytools3, MaxIm DL6, ASCOM drivers, all the manuals. I hooked up all the cabling, the USB-to-serial adapter for the mount, and the camera itself. All of the software components worked — I could control the mount and the camera and take pictures.

I also had to consider the condition of my camera. Had I damaged it beyond use? Beyond repair? I called SBIG technical support and described what had happened.

The support rep, Tim, was audibly chagrined. “Oh nooo! How did that happen? Are you sure?” I learned that the optical window is supposed to be firmly sealed, maintaining a bone dry chamber that keeps out dust, and prevents condensation and frost from forming on the sensor chip. (During a session, the chip is cooled to well below freezing to reduce the amount of thermal noise in the images.)

Next I exchanged some email with Bill in Santa Barbara who repairs SBIG cameras. He said I should send in the camera at my convenience. In the shop, he’ll affix the window, dry the camera severely in a chamber, and seal it all back up. He also suggested that I could probably use it this weekend, but with the seal broken it would “likely frost up, but then that usually dissipates after a while.”

With expectations of little or no success, Jane and I headed off to Amboy Crater on Saturday (April 2). The forecast was for ideal conditions. I’d never seen a Clear Sky Chart that black; little or no wind, severe clear skies, near perfect seeing, a low temperature forecast of 56°F. My plan was to experiment with all of the unfamiliar software and learn how to do this again.

With the mount polar aligned and all hooked up, I went to an old favorite as a test photo: the “Leo Trio,” M65, M66, and NGC 3628. At the site, the raw data looked really promising. Back home the next day, it was obvious that the image was marred by frost or condensation or both.

M65, M66, NGC 3628

The “Leo Trio,” NGC 3628 at the top, M65 and M66 below. Also a likely satellite streak in the upper left, and haze from frost or condensation on the imaging sensor. (Click for full resolution.)

Afterward, I spent 90 minutes or so learning to use PEMPro, and ended up with a polar alignment within one arcminute of the pole. It’s an excellent program, and I’ll be much quicker at it on the next go-around.

Meanwhile, there was some excitement among my fellow observers who were seeing the famous and very southerly Omega Centauri globular cluster. This object never rises more than a few degrees above the southern horizon. It’s known for being the largest globular cluster in our sky — probably the largest of all the globulars in the Milky Way’s halo. I couldn’t resist giving it a try.

Omega Centauri

Omega Centauri, 15 minute exposure (one exposure, not stacked). Astro-Physics Traveler 105mm f/6 refractor. SBIG ST-4000XCM one-shot color camera. (Click to embiggen.)

With that in the bag, I had to get Centaurus A, the famous “Hamburger” galaxy, just barely north of Omega Centaurus.

Centaurus A

Centaurus A, active galaxy. (Click to biggify.)

Then before crawling into the van for a nap, I shot a random field in the Virgo galaxy cluster, around M87.

M87 and Virgo cluster galaxies. (Click to embiggenate.)

M87 and several nearby galaxies from the Virgo cluster

After a nap, I did something I haven’t yet been able to do successfully in astrophotography: I shot some flat frames.

A “flat” is created by evenly illuminating the sensor to pick up imperfections in the optical train. It’s used to correct things like vignetting and dust spots, and produce a calibrated image.

With the new software for capture, SbigControl, and data reduction, CCDStack, making flats turned out to be quick and easy. I used my iPad with a grey image on the screen as a light source. I pointed the telescope to the zenith, and rested the iPad on top of the dew shield.

Here is my master flat, made by combining several raw images:

Flat image with dust specks and vignetting.

Master “flat” image taken in the morning after the previous shots, and used to calibrate the images. Notice all the dust specks! (Click for … god, why?)

Oh gracious, that seems like a lot of dust to me! I’m sure I (un)sealed my fate by opening the dry chamber of the camera, allowing a few specks to settle on the sensor cover glass.

All-in-all it was one of my most satisfying astrophotography expeditions. I’m really looking forward to getting the camera back from SBIG. I’m not expecting anything magic — it’s not going to take better pictures than these. But I do expect fewer images marred by frost haze. I imagine I’ll be able to shoot earlier in the evening and have the images be usable. With the modern software in place, I might be able to try some more ambitious projects.

Teaching bridge with a hand dealing machine

Here are five tables worth of hands ready for my next class. Each table gets boards one through four, in a distinctive board color.

Last month I took a leap and purchased a bridge hand dealing machine. The PlayBridgeDealer4 is very popular with bridge clubs and tournament managers for preparing pre-dealt hands and duplicating them across […]

Internet service has no maverick

If you’re like me, you have exactly two places from which to buy high-speed internet service: your phone company (mine is Verizon) or your cable TV provider (mine is Time Warner Cable).

That sounds like competition, doesn’t it? If you don’t like one, you can go to the other.

Why would I switch?

After nine years (and about $10,000) […]

Home theater upgrade, part 2, fixing HDMI

(Part one found here.)

First I’ll mention that the AV preamp I started out with, a Marantz 7005 purchased as B-stock from Outlaw Audio, turned out to be hopeless. It would never successfully handshake video output to either of my displays, even with no sources connected. Sometimes on a hard reboot, it would send some video, then […]

Home theater upgrade story (Part 1)

Old system:

Rotel RSX-1065 receiver
Panasonic TH-50P9UK plasma display
Old Pioneer DVD player
InFocus ScreenPlay 5700 projector
B&W CDM7NT 5.1 system, with broken tweeters on the front mains
Logitech Harmony One universal remote

Why upgrade?

The Rotel receiver has annoyed me for years with its few seconds of silence after mode switches (like Dolby Digital to PCM during a TV broadcast). It’s volume behavior […]

April Observing: Supernova and a Comet

The weather forecast for our favorite spot, Amboy Crater, called for decent conditions but high winds. (Why do we care about the wind? Here are four reasons I can think of: simple comfort, blowing charts and equipment, maintaining a target in a telescope, and blowing dust.)

The best forecast in the area was at our old favorite […]

Finally some observing weather

See Jane’s observing report from the same evening — some great binocular observing with Kemble’s Cascade.

The 20D mounted piggyback on the Traveler and Mach One GTO mount, hoping to catch comet PANSTARRS on its first opportunity.

Several months ago, David Green of the Santa Clarita Valley Photographers Association invited me to give a talk on astrophotography […]

“Why didn’t you just …”

Here’s one post that’s equally valid for bridge and computer programming.

Have you ever accomplished some task and had someone say “Why didn’t you just” do it some other way? Usually their suggestion is assumed to be the obvious or simpler way to do something.

In bridge, maybe you misplayed the hand, or chose a different lead on […]

Ruby gem problems around libv8, therubyracer, mac vs. linux, native extensions

I haven’t done a techie blog post for a while, and this “solved problem” keeps raising its head at work, so here goes.

Here’s the situation:

A ruby web app
Develop on Mac OS X
Deploy on Linux
Using bundler to control gem versions
Using therubyracer and libv8

You build your app on your Mac, install your bundle of gems using bundler, and […]

Kaiser Low Calorie Diet, Terrible Execution

Like so many of us, I need to lose weight. My doctor at Kaiser referred me to a new in-house weight loss program, a low-calorie “meal replacement” program. The program appears to be a franchisee of Robard Corporation’s “New Direction” program.

The program itself is very good. The class materials are current and instructive, and the high-protein […]