I've been taking advantage of clear, calm skies with not much Moon over the last few days to do RGB imaging (I'll go back to Hα as the Moon gets more full, weather permitting--and it does not look good for the next few days). So I've attempted 2 new objects and 1 previously-imaged target, all of which I find quite difficult, and one very easy target.
First, the easy one, done before I fixed my gear issue: the Double Cluster in Perseus. This pair of bright open clusters is easy to find and image, and is one of the targets I tried very early in my astroimaging "career" via afocal eyepiece projection. I did it this night as a "warm up" target while waiting for M77 to rise. The only difficult thing about the Double Cluster is that it is so large it doesn't easily fit in my field of view. I opted for a 3-panel mosaic, stitched together using Photoshop's "photomerge" feature. Here it is:
Date: 24 Oct 2014
Subject: NGC 869 & NGC 884, Double Cluster
Scope: AT8IN+Antares 0.5x focal reducer
Filter: Baader Fringe Killer
Mount: CG-5 (Synta motors, PicGoto Simplificado)
Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1 (Win 7 ASCOM)
Camera: DSI IIc chiller at 2.50 A, 16.5 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 27+32+26x60 s
Stacking: Neb 3, bad pixel map, bias included, no flats, normalize first, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.289 Crop; Wipe:Color & brightness 100,80,100%; Develop 80%; HDR:Optimize; Color:Scientific, 300%; Life:Moderate; Track: 2.5 pix; Magic shrink 1 pix. Photoshop CC 2014 Astronomy Tools Photomerge; Increase star color; Healing brush; Astro Frame.
When it rose, I switched to M77, Cetus A, which like most large galaxies has a large black hole in its nucleus (although this one is supposed to be bigger than average). This was a new target for me, and it proved difficult as my RA guiding (and, hence, my DEC too, because when one is bad the other generally is also) was haywire due to the bad gear mesh. I was happy to get some of the faint outer spiral arms to show up, but I probably could do better with this subject. It probably would look better with 600 s subframes rather than the 450 s I used, but the core is pretty bright and probably would have been severely overexposed at 600 s.
Found M77 (Cetus A) with Astrotortilla by synching from a "blind" plate solve. Conditions were above average, but guiding was terrible. I need to look into why my guiding is suddenly so bad; probably some gears need adjusting. A warm night for this time of year, chiller at 2.5 A, 14-5.5 °C. Got up to do a meridian flip and discovered I didn't need to; the mount was aligned so it wasn't going to bump. As my subframes came in I looked for the dim spiral arms and could not see them even with extensive stretching, so I was delighted to find they were easily apparent after stacking.
Date: 24 Oct 2014
Subject: M 77, Cetus A
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: 48x450 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 80.11%; HDR:Reveal core; Color:Scientific 250%; Life:Moderate; Deconvolute: 3.0 pix; Track 7.1 pix; Magic 1 pix (twice). Photoshop CC 2014 + Carboni Astronomy Tools Increase star color; Deep space noise reduction; Healing brush; Astroframe.
At this point I decided something was wrong and tuned up my gear mesh as noted above. I got much better guiding in the session that followed (sub arcsec) after resetting the mesh on my RA gears. This is a target Kier suggests (in The 100 Best Astrophotography Targets) would be difficult with a one-shot color camera, so I decided to use a light pollution filter (this target was in the light dome of the city to my north (Provo, Utah) most of the night) and go with 600 s subframes. It’s a beautiful object. It looks like it has a lot of Hα, though I wonder if some of the reddening is just due to the light passing through the dust of the Milky Way’s disk plane. The core, which Wikipedia reports is an H II region, is quite bright, easily visible in my imager at 1 s exposures. I was quite pleased with this image.
Date: 28 Oct 2014
Subject: IC 342, Spiral galaxy in Camelopardalis near Milky Way galactic plane
Scope: AT8IN
Filter: Baader UHC-S
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, 3-7 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 30x600 s
Stacking: Neb 3, bad pixel map, bias included, no flats, normalize, trans+rot align, 1.5 SD stack.
Processing: StarTools 1.3.5.289 Crop; Wipe 75%; Develop 87.49%; HDR:Optimize; Color:Scientific 225%; Life:Moderate; Deconvolute: 2.0 pix; Track 5.0 pix, Smoothness 84%; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Increase star color; Deep space noise reduction; Levels with a layer mask; Astroframe.
Finally, with one last night of good weather I decided to return to the Nautilus Galaxy, because I just wasn't satisfied with what I got the last time out (see my earlier post). The combination of UHC-S high contrast filter and 600 s subframes worked so well on IC 342 that I decided to try it on the Nautilus. Guiding was still pretty good. I might be able to do better, but this is still the best Nautilus I have gotten so far. I tried layering this stacked image with the one I got a few nights ago using 480 s subframes, but I like the pure 600 s subframe image better. I did all my finding with Astrotortilla+Picgoto, both originally and after a meridian flip. It worked great.
Date: 29 Oct 2014
Subject: NGC 772, Nautilus Galaxy
Scope: AT8IN
Filter: Baader UHC-S
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, 3-7 °C
Acquisition: Nebulosity 3.2.1, no dither
Exposure: 38x600 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:Color & brightness 75%; Develop 90.05%; HDR:Optimize; Color:Scientific, 265%, cap green to yellow; Deconvolute 2.3 pix; Life:Moderate; Life:Less=more; HDR:Optimize; Track Grain size 10.2 pix, Smoothness 81%; Magic:Shrink 1 pix; Rotate 180°; Repair:Warp. Photoshop CC 2014 + Carboni Astronomy Tools Deep space noise reduction; Levels (darken); Layer mask; Astro Frame
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