Andromeda Again

The Andromeda Galaxy is one of my very earliest deep sky astrophotography targets. I remember looking at it through a small telescope when I was young, and seeing just a fairly unimpressive blob of light. When I began playing with my point-and-shoot digital camera, this was one of the first objects I tried via afocal, eyepiece projection astrophotography.  The first attempts were little more than blurry blobs, but I was thrilled to see dust lanes I could not see visually. Since then, each fall I've tried again to see if I can improve on previous images. This first picture was taken with just the point-and-shoot camera with the lens zoomed up.

1 Nov 10: Andromeda wide field, taken piggyback on the telescope mount with just the camera (not through the telescope).  Stack of 24 RAW frames (Deep Sky Stacker, dark frame subtracted).  Stretched via GimpShop.  PowerShot A560 camera at 800 ISO, f/5.5 (4x optical zoom), 256 s exposures.  Both the big satellite galaxies (M32 and M110) are visible in this image. if you know where to look.

The second image was taken using eyepiece projection through a telescope (a Meade 4501 4.5" Newtonian reflector). There's lots of vignetting and you can see the edge of the round field of view, but I was thrilled to see the satellite galaxies and some dust lane structure.

28 Jan 2011: M31, M32 (to right), M110 (upper left of center).  Stack of 22 RAW images (DSS).  Afocal, PowerShot 560 camera at f/2.6 on camera, 800 ISO, 32 s exposures, dark subtraction in camera, Sirius-Plössl 40 mm eyepiece projetion (so system f/1.16).  GimpShop Curves & Levels.  Dust lanes faintly visible all the way around, 2 in the direction of M110.

Getting a real astrophotography camera and switching to prime focus astrophotography was a huge step up. By this point I had also gotten my Astro-tech 8" Imaging Newtonian telescope, another big step up. In the fall of 2011 I spent many nights putting together a panaroma. My field of view was small so it took quite a few images to do this.  Getting the images to blend together smoothly was a big challenge.

In December 2011 I got a used Orion Short Tube 80 mm refractor.  This gave me a bigger field of view. The following fall I used the big field of view to try to capture the whole galaxy in one frame. I had also learned better color processing. By this point I had developed a lot of the protocols I still use for documenting my images. 

An easy find, obviously, as M31 is a naked eye object.  Lots of smoke in the air tonight.  I had to play with exposures a lot to avoid blowing out the core.  300 s was too long, and eventually I settled on 180 s subframes.  Guiding is so easy when imaging at this scale!  But I couldn’t get dither to work because none of the settling options were large enough for guiding at this focal length with my mount.  I removed the Meade IR filter from the DSI as the Baader Fringe Killer filter I was using also cuts IR.  I'm waiting on a new power supply for my chiller, so it is still not working and the CCD was at about 16 °C for the run.

Date: 18 Sep 2012

Subject: M31, Andromeda Galaxy

Scope: Orion ST80 + 0.5x Antares telereducer

Filter: Baader Fringe Killer (DSI IR cut filter removed)

Mount: CG-5 (Synta motors)

Guiding: AT8IN+High Point Scientific coma corrector + DSI Ic + PHD

Camera: DSI IIc (no cooling)

Acquisition: Nebulosity 3.1.1, no dither

Exposure: 64 x 180 s

Stacking: Neb 3, bad pixel map, bias included, normalize first, trans+rot align, 1.5 SD stack

Processing: Digital development with weak sharpening, curves, power stretch, GreyCStoration (on background layer) saturation boost in Neb 3; CS6 2 layers: background layer Astronomy Tools color blotch, deep space, space noise reduction. Sharp layer was high pass filtered.  Combined the two with a Gaussian blurred layer mask over the dust lanes.  Horizontal band noise reduction and star color enhance the flattened image.

My 2013 effort was not a huge improvement over 2012. I think it was a bit over processed as I attempted to bring out color in the spiral arms.

Conditions tonight are absolutely gorgeous.  However, I'm having terrible problems with the RA tracking on my mount.  I guess I've let it crash one time too many.  I can only get it to track by heavily east-weighting; otherwise, the motor slips and the gears don't turn.  I've seen hints of this problem before, but tonight it is severe.  I may have to get a new set of motors, but I hate to invest any more in this mount.  When the tracking was working, the guiding was excellent, about the best I've ever done.  

Date: 30 Sep 2013

Subject: M31, Andromeda Galaxy

Scope: Orion ST80 + Antares 0.5x focal reducer (on 1” nosepiece, so ~0.65x)

Filter: Baader UHC-S

Mount: CG-5 (Synta motors)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.1.1a

Camera: DSI IIc (chiller at 2.25 A, -5 °C)

Acquisition: Nebulosity 3.1.8, no dither

Exposure: 42x300 s

Stacking: Neb 3, bad pixel map, bias included, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.255 Crop; Wipe:Color & Brightness; Develop 85.22%; Sharpen; Deconvolute 3.0 pix; Color:True Color, Dark Sat 4.0, Bright Sat Full, Sat 225%,; HDR:Optimize; Life:Heavy; Track Denoise; Magic:Shrink 1.  CS6+Astronomy Tools Increase Star Color; AstroFrame.

That finally brings me to the present. Rather than try to get everything in one image, this year I decided to try a 2-panel mosaic. I still don't have much color in the arms, but rather than try to force the issue I opted to just go for what my normal processing yields. I think this is the best so far.

I'm not satisfied with my M31s so far, so I'm trying again on what is one of my oldest deep sky targets. I'm trying a 2-panel mosaic of Andromeda Galaxy. Conditions are excellent: cool, clear, and calm. Chiller at 2.5 A, 4.5 °C. My guide scope is still out of focus; I must not have fully inserted the camera. I plan to do the north end of the galaxy as I image up to the meridian, then I'll do a flip and move to image the south end. Fixed the guider focus issue after the meridian flip. Guiding, for the moment at least, is improved. Excellent performance all the way until dawn. This target is deceptively difficult because of its size and very high dynamic range. I think the bottom and top of the mosaic still don’t match up very well. I could spend a lot more time trying to process this better, and probably will, but I think this is my best Andromeda so far. 

Extensively reprocessed in this revision. Some of the chief changes were more deconvolution to bring out detail and lots of layer mask work to keep the overexposed portions from standing out too sharply and to darken the background sky.

Date: 2 Oct 2014

Subject: M31, Great Andromeda Galaxy

Scope: Orion ST-80 + Antares 0.5x telereducer

Filter: Baader UHC-S

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, 4 to 2 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: Upper, 49x300 s, Lower, 57x300 s

Stacking: Neb 3, bad pixel map, bias included, no flats, OSC nebula filter extract, normalize, debayer and square, trans+rot align, 1.5 SD stack.

Processing: (attempting to do the same thing to upper and lower frames) StarTools 1.3.5.289 Crop; Develop 87.49%; Color: scientific, 250%; Deconvolute 2.0 pix; Life:Less=more; Track Grain size 7.2 pix, Smoothness 70%; Magic:Shrink 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Healing brush; Photomerge; Levels; Star color enhance (twice); Increase local contrast; Astro Frame.