File:Gibbous Moon - 21 Nov. 2012.jpg

Gibbous Moon - 100% crop from 16 stacked subexposures (best 16 out of 360)

Image Scale = 0.44 arc-second/pixel

Date: 2011/11/21 - 19:04 to 19:57 EST

Exposure: mixture of 1/250 sec at ISO 200 and 1/125 at ISO 100

Telescope: Celestron EdgeHd 800 -- approx 2000mm at f/10 Camera : unmodified Canon T2i = 550D Mount: Astro-Physics AP900 -- rough polar alignment (no drift alignment)

Processing:

1) Focusing via EOS utility live view, exposures made from live view mode (EFSC active, so no mirror slap or first shutter curtain shake?). Three individually focused sequences were done. Two were at ISO 200 and one at ISO 100. The Feathertouch motorized focuser was moved 20 or 25 steps between groups of about 25 shots at each focuser position. The total range in each sequence was about 75-80 steps between closest focus and farthest. The hope was that some of the shots in each sequence were near optimal focus, and these would be selected later by stacking software.

2) 16 best of 360 individual shots selected, centered and cropped to 4400 x 3000 using Planetary Imaging PreProcessor (PIPP).

3) These 16 shots were split 9 ways in a 3x3 grid (with overlap), into 1800 by 1200 pixel panes using Photoshop CS5, since neither Registax nor AutoStakkert 2 would handle the large 4400 x 3000 frames. (Zerene stacker PMAX mode could handle them, but the output was not good.)

4) The 16 sub-shots in each of the 9 panes was passed to Registax for stacking, using 50% drizzle, yielding one 3600 x 2400 output stack for each of the 9 panes. "Wavelets" processing was done on each pane, using the same settings. These setings were far from optimal, since the whole wavelets thing is a mystery to me.

5) The 9 panes were then combined into a mosaic using Auto Pano Pro 2.