Please click on the image to see a full-size image

Object:
 M51 - The Whirlpool Galaxy
Date(s):
 14 March 2013
Location:
 Rancho Hidalgo, NM
Telescope:
 LX200 10" at f/10.86
Mount:
 Meade SuperWedge on pier
Camera:
 SBIG ST-11000M
Single-Shot Color:
 No
Luminance:
 15 2 minute images bin 2
Red:
 15 2 minute images bin 4
Green:
 15 2 minute images bin 4
Blue:
 15 2 minute images bin 4
Comments:

Could not get a good guide star onto my guide chip in the ST-11000 camera. Decided to take short unguided images of two minutes duration.

The result surprised me. Sure beat my earlier film shots:
http://www.astroshow.com/astropho/m51p.htm
http://www.astroshow.com/astropho/m51ok.htm

and my earlier ST-7 camera shot:
http://www.astroshow.com/ST7pho/m51c.jpg

In order to take two minute unguided images, you have to have very good polar alignment. I always use the "iterative alignment" method that I invented (at least I independently invented it in December 1994 since I was unaware at that time of anyone using such a method.) I didn't want to waste a lot of time doing the "drift" method. It always sounded like the "drift" method wasted a lot of time and would not be as accurate as iterative alignment. I used the iterative alignment method to align the scope in New Mexico when I first set up the scope.

I probably should do a 5 minute test to see if I can get away with 5 minute shots with no star trails...