This shot represents the inner 15 arcminutes of the Great Andromeda Spiral. It represents 110 minutes of exposure time, and is a (LG)RGB image. During the RGB phase of imageing, it was seen that the green image had significantly more contrast in the dark lanes than the other colors. This is because the dust is reddish seen here. So a few extra green frames were combined into the L channel for increased contrast.

Processing: Dark, bias frames subtracted, then all 11 frames of 10 minutes each were median combined as to not saturate the core. This created the L channel. Next the RGB frames, also shot at 1x1 binning were combined to produce the color data. On both L and RGB, DDP was applied to allow for such a huge dynamic range to be represented on one image. The weak kernel filter was used. The L image was additionally processed in AIP with 5 iterations of RL deconvolution, high frequency components only. Finally, the Synthetic L and the RGB were combined to form this image.

            

            
 Left:  Film image taken with the same instrument
            on gas hypered tech pan emulsion.  This is
            only a 5 minute exposure, and the core was 
            too burned in to recover useful detail.  Same
            instrument and location.

            
Click on image to enlarge

      

Instrument:  12.5" f/5 Home made Newtonian
Platform:  Astrophysics 1200 QMD
CCD Camera:  SBIG ST7E w/Enhanced Cooling
Exposure:  (LG)RGB = 110:30:50:30 
Filters:  RGB Tricolor
Location:  Payson, Arizona
Elevation:  5150 ft.
Sky:  Seeing 1.9sec FMHW, Transparency 8/10
Outside Temperature:  15 C
CCD Temperature:  -25 C
Processing:  Maxim DL, Photoshop, PW Pro.