Tuesday, February 16, 2016

Proof of concept

After more than a year of working on the photography studio and other new homeowner tasks (read: chopping back those monstrous mountains of Carolina jasmine and Lady Banks roses, not to mention septic work and other stuffs) I've been re-bitten by the astronomy bug. Mostly this amounts to my having more time and less exhaustion, directly attributable to turning in the Chicken Ranch book manuscript. The new house had significant appeal for me because--while not close to being a true dark sky site--it was much darker than our old neighborhood. Last Thursday, I hauled out the new(ish) Atlas mount and set up the telescope for the first time ever at the new place. Here's how it went:

Tonight I set up my telescope for the first time at the new house. I'd only intended to do a polar alignment and mark the tripod's position for quick set-up in the future, but crescent moon was so tempting that I went in and brought out the scope. Bug and Fairy Girl came out and oohed and aahed. Seeing was excellent tonight, with crisp views and little turbulence in the upper atmosphere. I used 20mm and 9mm plossl eyepieces, then barlowed the 9mm. The mountains and craters around Mare Crisium were super sharp, and there was lots of contrasty detail along the terminator. Then I swung the scope around and took a quick look at the Orion nebula. It was very clearly visible as ghostly white wings (the color one sees in photos comes from long duration exposures). Even the Trapezium was crisp and distinct, very easy to pick out.

The new place is so much better to observe from than the light-polluted old neighborhood. It's not anywhere near being a dark sky site, but there is much less local light pollution. Even so, there's one floodlight on a neighbor's garden shed that shines directly onto my observing area and really messes up night vision. I'm going to have to construct some sort of light block above the fence there. All in all, though, once I get it set up the way I want, this is going to make a nice backyard observatory.
That was prelude. I've long been fascinated by astrophotography, and in fact took my first (very bad) astrophotos when I was 13 using a Canon AE-1 with a telescope adapter. Last year, The Wife gifted me with a Canon Rebel T3i modified by Hap Griffin to be more sensitive to the Hydrogen-Alpha light that dominates many emission nebula in the night sky. I've not had a chance to use it until Saturday, when I set up the whole shebang in the back yard and made a test run.

One big astronomical target that's long held my interest is Barnard's Loop. It's the crescent remnant of an ancient supernova explosion in the constellation Orion that's invisible to the naked eye. The modified camera should be able to pick it up, though. The evening started off quite nicely, as I ran the Atlas mount through a three-star alignment and it went swimmingly. I mean, it nailed alignment without the tears and cursing I usually suffer. I set up the T3i on the telescope using a homemade piggyback mount, my Canon 50mm 1.8 mark I lens (a favorite for infrared photography) and a new Kenko fog filter I recently acquired. I didn't have an intervalometer compatible with the T3i, so I was limited to 30 second exposures, but I hoped that would be enough--eternal optimist, that's what I am. Here's the result:

Now, I'm the first to admit this is nothing to write home about. The white balance is way off, there's coma all around the edges and all sorts of little technical issues that are wrong with it. I messed up shooting my dark frames and didn't bother with flats. The waxing crescent moon also contributed to the light gradient in the image, which is why moonless nights are best for astrophotography. But dang, look at what's right--the elusive loop is clearly visible, a faint crimson crescent stretching from Bellatrix in Orion's shoulder to Rigel in his foot. M42, the famed Orion nebula, is so bright it's blown out in the sword. And look at the belt--there's the Flame and Horsehead nebulas right there off the leftmost star. And this is all captured via a basic, standard 50mm camera lens. I have not attempted prime focus photography yet, which entails using the telescope as one big 762mm lens. Tracking held steady, so I'm confident I could go for exposures of five minutes or more with no significant star movement at this scale. I've got a guide scope, however, and just need to get a dual mount so I can run them through a computer and enjoy the rock-steady tracking for deep-space objects such a setup enables. Am I looking forward to that? You bet.

I might just get the hang of this astrophotography thing yet.

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