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I reassembled the wiring harnesses for my equipment along more functional lines.  I had put things together by type of connection which was pretty silly in hindsight.  So now I have two four-cable harnesses for each Canon 350D (one DC power line, one serial line for the shutter release, one USB connection, and one heater strip for the lens).  They're bundled with twist ties every 6-8 inches.

I also dug out a Y-adapter for the shutter release.  That lets me control both shutters with one DSUSB release.  Unfortunately, as I posted here a long time ago, Canon's software can't handle more than one camera at a time.  But you can "cheat" by only connecting one up via the USB connector and splitting the shutter release cable.  So long as you don't want to do anything fancy (e.g., change ISO settings), this works.  Of course, you also need to have lenses with similar properties which mostly means f-stop, or else you have to set things up so they same exposure is sensible for both.

Anyway, it is all wired up and seems to work fine.  There are a few "interesting" behaviors with this arrangement.  When the shutter release cable is connected via the Y-adapter, turning on/off one camera causes the other one's shutter to fire (it it is on, duh).  If I turn then both on simultaneously, this doesn't happen.  Since I have mirror lock turned on on both, it's important to watch for that to avoid having them out-of-sync.

I also discovered that ImagesPlus 2.75 has no means to not download the images and leave them on the camera.  That's annoying since I would rather leave both sets on the camera.  I could upgrade and see if that helps, but the upgrade to the latest version is $120.   I'm trying to avoid the expense right now and it would never arrive in time for the Summer Star Party anyway.  MaxDSLR has the same problem.  DSLRFocus 3.3.15 (beta, never made it out of beta) will leave the images on the camera and it works well enough even if it has been orphaned by its author.

I need to do a few test flats and darks.  Well, I can just accept a 50% duty cycle and have the camera do its own dark frame subtraction, but I still need to do some test flats.

But first priority is to get my 7-year old's new bicycle built tomorrow.  We bought a 7-speed online, "some assembly required," and he's ready for it. 

Despite the full moon, I got out with my AstroTrac, modified Canon 350D and Borg 45ED.  With the light-polluted skies of NYC, I put a Lumicon H-alpha filter on and shot as low as ISO 100 in order to test with 5-minute exposures.  The conclusion?  The AstroTrac is tracking just fine for 5-minute exposures.  But my shots show bloated stars and some indication of what appears to be coma which is not centered on the sensor center.  I had thought the bloating might be due to this camera having a clear filter.  It was modified by Hap Griffith two years ago and I think I asked for a clear filter.  However, I also have a Hutech "UIBAR-FF" in place which is supposed to provide both IR and UV cutoffs, so I really wasn't expecting any bloating due to IR coming through.

I do have two remaining problems.  First is that I have something on the filter/sensor/something that really calls for flat fielding.  This was most noticeable in my images of M31, but shows up weakly even in star fields so long as the background is exposed enough to not be really black.  Second, I really need dark frames, particularly at higher ISO speeds.  The 5-minute exposure with in-camera noise-reduction turned on is significantly better looking than the one without.  Ugh.  I don't like the idea of a 50% duty cycle for imaging.   That starts to put me back at film-like times for imaging.  Okay, not quite, but still.  Around here, night-time temperatures are fairly stable so I could probably get away with taking a few dark frames and manually calibrating later.  I'm not sure how well that will work when I'm in the boonies and the temperature is falling all night.

Oh, and I have to rearrange the wiring harness I so carefully put together last summer for CCD imaging tracking with the Losmandy GM8.  I need things arranged a little differently for the AstroTrac.

Uhm, and I need to make some kind of stand-off to elevate the ball mount further off the AstroTrac.  When looking near the zenith with the Borg 45ED, the camera hangs down low enough to bang into the AstroTrac.  I'd also like to be able to mount two cameras instead of the current one, but that will take a little work in the garage I'm not sure I have time for before we leave. 

Well, I managed to get out and use my AstroTrac under reasonably dark skies just north of Cape Girardeau on the night of July 13/14.  The moon didn't set behind the hills until around 1:30 am, but I shot across the sky from it at M31 using my Borg 45ED.  I used the laptop for control since my TC80-N3 is shot.  I had an AC inverter to keep the laptop alive, but it didn't have enough power and kept turning itself off. Ultimately, I was limited by when the laptop shut down.  Since I was travelling light, dew was also an issue (no heater system) and I kept having to pull off the lens and use the car heater to clear the dew.

The biggest issue is tracking.  There are two things I've noticed.  First, it's hard to polar align when the polar alignment scope has a scale problem.  Second, each click stop in the AstroTrack for rotating the polar alignment scope to a new position has a slightly different take on where the pole is.  The end result was that my 5-minute exposures all show slight trailing.  I had the Canon 350D set to ISO 800 as a bit of a compromise between sensitivity and exposure length, but it looks like I'll have to crank that to ISO 1600 and shoot more, shorter exposures.  I need to gain some experience with this before next week when we go to the Summer Star Party.  With the full moon and living in Brooklyn, I think I can get away with tests using the Lumicon "hydrogen alpha" filter to cut down the light levels enough to still do 3-6 minute exposures. Unlike a telescope, I'm not quite sure how I can get the AstroTrac aligned well.  I don't think I can practically do a drift alignment and I was hoping for short exposures to avoid the need to do so.

Well, Richard Taylor of AstroTrac got my polar alignment scope back to me before we left on vacation. Alas, the new scope has the same image scale problem as the old which makes it a bit difficult to align. Not impossible by any means, just more difficult. So I packed everything up and carried it with us to Missouri.

We had the chance to spend a night near Sullivan, MO, under some very nice dark skies. While Sullivan itself put a small light dome on the northwest horizon from my sister's cabin, the south was quite dark, so much so that a cloud drifting across the Milky Way produced a dark blotch on the star field without any relected light at all. So I set up the AstroTrac and switched to my Borg 45ED to shoot the Rho Ophiuchus region since the conditions we okay (not great with moderate humidity and some clouds). But it was not to be. The previous day (July 4) I had had trouble with my modified TC80-N3 cable release. The TC80-N3 was modified by Hutech some 3 years ago (or was it 4?) when I bought the Canon 350D and Borg 45ED from them. I had thought it merely needed a replacement battery so I picked up on they way to the cabin. But it then stubbornly refused to work. Almost. As I messed with the cable, it fired for a 4-minute exposure when the cable was bent just a certain way. Hmm, the cable had been frayed near the strain relief, but worked fine the last time I was out (over a month earlier) and besides, last year I had coated that part of the cable with "Plasticoat" when I first noticed signs of fraying which I had though should have protected it and prevented futher problems. Still, keeping it bent at a funny angle to get in my shots wouldn't be too bad. Sigh. No such luck. It simply refused to work a second time.  After about half an hour of trying, I packed it in.

A couple of days later, I had the time and tools to attempt a repair by chopping a few inches off the cable and resoldering the leads. But no luck there either. The timer display looks and operates just fine, but the signals are not getting through. No idea why. Not even the "manual" pushbutton release works. So this trip is a bust since shooting 30-second exposures (the longest possible without the cable release) would be at best painful and at worst futile since I would have to push the button by hand (well, I could use the 3-second timer).

I've ordered a couple of TC80-N3 clones from Hong Kong that already have the correct cable attached for the 350D. Hopefully, they will arrive in time for our next trip in at the end of July.  If not, I will at least be able to control the cameras via the computer serial port adapter, but I was hoping to be computer-free except for focusing. Oh well....

Back at NEAF, I purchased an Astrotrac unit hoping to put it to good use for wide-field astrophotography. I had been looking at the unit for the past couple of years since it first showed up in a few magazines and saw the early units at NEAF. So finally I got my own. I got a reasonably clear nigt for testing in NYC almost immediately and discovered the polar alignment scope, which is supposed to be the same as the Losmand polar alignment scope, had a problem. The magnification is slightly off compared to the etched reticle. For those of you who may have purchased a CG11 mount several years ago (not sure how long) , this might ring a bell. David Kodama explains that Celestron had some scopes made that had the wrong image scale which threw off the reticle alignment. It would appear the Astrotrac has been bitten by the same problem.

After an email exchange on April 30th, I sent off the scope to Richard Taylor at Astrotrac for inspection. He's plead a long string of bad weather (it is the UK after all) for not being able to check out the scope, but I suspect that it is also partly a busy travel schedule for what is, after all, a small company trying to sell a nice product. He offered to simply replace the scope to get me going again, but that was delayed while he waited for a new shipment. Finally today he says it should go out in the mail. Alas, it will probably not arrive before we leave for a vacation to Missouri where I had hoped to put the Astrotrac to use. Last month we went into upstate New York with dark skies and no Astrotrac, this month it's to Missouri with no Astrotrac, but I should have it in time for the Summer Star Pary in Massachusetts. I hope.

I was interviewed a month or two ago for an article in Time Out New York Kids about astronomy activities with children.  The call went out from Rich Rosenberg or the Amateur Astronomer's Association here in NYC to all members and I guess I was the first to get in line.  Our neighbors saw the article before I did and brought it over.  Our two boys immediately wanted to know if this made me famous .While I'm not quite famous, it is pleasing to see the information in print and I hope it will prompt more parents, even in urban places like NYC, to go out and look at the night sky with their children.  The moon is an easy thing to observe and with only a little research, every parent can explain why it keeps changing.  Some of the brighter constellations are visible, if not from Time Square, at least from parks and side streets where you avoid the glare from the local street lights.  Have you tried to spot the Big Dipper this month?  It's nice and high overhead and slightly north just after it gets dark.

The imaging conference (NEAIC) and the Telescope Show (NEAF) are over for this year.  The last few days have been pretty hectic and I'm just now catching up.

On Friday, I attended a spectroscopy workshop led by Olivier Thizy where he walked us through the process of using a spectrum taken with a diffraction grating in front of a  Canon 350D (Digital Rebel XT) which we then used to measure the rotational speed of Saturn.  What a cool application using completely off-the-shelf components.

For NEAF itself, Maria and I worked in the children's area this year both days.  On Saturday we helped the children build 3-D models of the constellation Orion and on Sunday we built models of the Big Dipper.  Both events worked out well and were well attended with about 25 models built during the two days.  We spent a little time which (almost?) every child helping them to see the constellation then talking about how the stars are really at different distances.

I did come back with a couple of new "toys."  Apart from the new Sun T-shirt from Inifi-Tees (appropriate dress for the PS 102 lesson on the sun), I also came back with a couple of tektites (melted material ejected from a meteor crater), a couple of "astro-blasters" designed to show how momentum transfer can result in humongous explosions in supernova, a SolarScope™  suitable for group viewing of the Sun's disk in white light (pity we're close to the sunspot minimum right now), and an AstroTrac™ for taking long-exposure wide-field images with just my DSLR.

But now its back to work.  There's still a month left for the PS 102 Astronomy Club and I have plenty to do for that. 

The plenary session by Ken Crawford provided some interesting ideas on how to bring out image details.  His focus was on techniques appropriate to what he labelled "technical art" wherein he spends quite a bit of time using various image masks to selectively process parts of the image to bring out local features.

I then attended Thierry LeGault's presentation on solar imaging.  Thierry was a wonderful speaker; in spite of English being a second language (his native tongue is French), his sense of humor was evident as was his skill in solar imaging.

I picked up a number of new ideas on how process images from Richard Berry's talk where he demonstrated some common image problems and how to solve them using the program AIP4Win written by him and Jim Burnell. This one definitely sends me home with a few new tricks in my bag.

The last talk I attended was on the topic of "Guiding on the Cheap" given by Craig Stark of PHD "fame."  PHD is his autoguiding software package that runs on Windows and Mac OS X; PHD stands for "Push Here Dummy" and is supposed to take the guesswork out of setting up your guider.  Craig was a wonderful speaker full of good tips and promoting a lot of common-sense in his approach to autoguding.