astroimages
Darin E. Fields' Astrophotography Pages
 

M51: The Whirlpool Galaxy in Canes Venatici

Right Ascension 13 : 29.9 (h:m)
Declination +47 : 12 (deg:m)
Distance 37000 (kly)
Visual Brightness 8.4 (mag)
Apparent Dimension 11x7 (arc min)
More information on M51

Exposure:75 minute LRGB exposure (L=30 minutes (30 x 60sec.), R=15 minutes (5 x 180sec.), G=15 minutes (5 x 180sec.), B=15 minutes(5 x 1800sec.))
Camera:ST-237 cooled at -30c
Guiding: ST-4 on ST-80 @f/10
Telescope: f/4 8" newtonian
Mount: Losmandy G-11
Processing:Maxim/DL, Photoshop 6.0
Date:4-04-02
m51-lrgb-2a:

Using the same raw data as the image above, on this image I applied DDP processing and a mild unsharp mask in Maxim/DL to the luminance frame and manipulated the color curves a bit to reduce the amount of green. Thanks to Mike Chapa for the processing suggestions.
m51-lrgb-new: