Side note: I got to see yesterday's partial solar eclipse through a Lunt Solar Systems Hα solar telescope (owned by the Brigham Young University Astronomy Club; they were out observing the eclipse and doing public outreach). These are extremely narrowband scopes, and the view was astounding; prominences were visible all around the solar limb. Now I want a narrowband solar scope (you can't get enough contrast to see prominences with a simple filter like my Baader Hα imaging filter), but they ain't cheap!
A while back I mentioned Astrotortilla. Astrotortilla is a plate solving program, which means it looks at the stars in your image, matches the patterns with patterns in a database, and tells you where in the sky you are pointed. It's also a Windows "wrapper" program, which means it can communicate with and control Windows ASCOM-based imaging programs (such as Nebulosity 3) and mount control programs (such as PicGoto server). I played with it a while back and didn't get it to work consistently, so I moved on.
A couple of days ago I ran across this excellent tutorial on how to set up and use Astrotortilla. That motivated me to try again. One of the key things I found should have been obvious, which is that because my Meade DSI IIc camera does not have square pixels, it is essential to square the image before attempting a plate solve; otherwise the shapes of the asterisms are wrong and are not recognized. Anyway, after squaring things up I was able to plate solve saved images.
So last night I decided to try to image the Nautilus Galaxy. My prior efforts on the Nautilus were less than satisfactory. This big galaxy is pretty far away and hence it looks small and not terribly bright, so for me it is quite a challenging target. Conditions were poor last night (intermittent high clouds) and I had significant guiding issues as well, which improved as I played with the mount's balance. However, another part of the session was a huge success: I finally got Astrotortilla working, and it is awesome!
Specifically, I imaged up to the meridian after finding the object in my typical way, by synching the PicGoto on β Ari and doing a successful goto. After doing my meridian flip, the scope was at an awkward angle where I had trouble getting my old back contorted to be able to aim accurately through my Telrad sight. Because I had been successfully plate solving on some saved test images, I decided to try using Astrotortilla to synch rather than actually centering a bright star. At first I let the program move the mount too, and that was fouled up because Astrotortilla obviously didn't know which side of the meridian the mount was on, and headed in the wrong direct. So I settled on just using it to synch the mount through ASCOM, then selecting my target and doing the goto through the Cartes du Ciel program's interface. Cartes du Ciel / PicGoto does know how my mount is oriented, because I tell it in a software setting. That worked marvelously. So no longer do I even need to find and synch on a bright star; just point somewhere near my target and let Astrotortilla do its thing. And it is FREE! It doesn't get any cheaper than that. AMAZING!
The Nautilus Galaxy image itself is still less than satisfactory, but I do see traces of an outer arm or star stream to the left of the core; I didn't know that was there.
Date: 23 Oct 2014
Subject: NGC 772, Nautilus Galaxy
Scope: AT8IN
Filter: Baader Fringe Killer
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1k (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 5-7 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 22x480 s
Stacking: Neb 3, bad pixel map, bias included+flats, normalize, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.289 Crop; Wipe 80%; Develop 82%; HDR:Equalize; Contrast; Life:Moderate; Color:Scientific 299%; Track 9.9 pix, smoothness 80%; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Deep space noise reduction; Levels (layer masked); Increase star color; Astroframe.
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