The Andromeda Galaxy

350mm, F/4 Mirror Lens


Well, I just had to try it.  On 8/14/05, I attached a telecompressor to the 500mm, F5.6 mirror lens I recently started experimenting with.  This converted it to a 350mm, F/4 lens.  I picked the Andromeda Galaxy as a test subject and took about a dozen 130 second images and 3 dark frames with this combination.  I also took a longer, 260 second exposure and a matching separate dark frame.  Of course, this object could use 10 times the exposure to bring out all it's glory, but I was just playing around to see how well the telecompressor worked. 

 I used IRIS  to stack the images and clean up noise and a light pollution gradient.  After the preliminary processing, I used Photoshop Elements to color balance and crop the image. 

This lens combination on my Canon Digital Rebel is equivalent to a 560mm F/4, 35mm telephoto lens.  As I feared, the lens still suffers from distortion the further you get from the center of the frame.  I can minimize it by cropping, but distortion is still evident even in the cropped image.


The Andromeda Galaxy.  This is a cropped image of a stack of twelve 130 second exposures  all taken with a Canon Digital Rebel at 800 ISO using a 350mm F/4 mirror lens.  Click on the image to enlarge.



Here is a view of the core of the Andromeda Galaxy with only minimal processing to color balance and slightly sharpen the image.  This is closer to a what you might see visually in a large telescope, minus the color, of course.   Click the picture to enlarge.


I rotated the image so that south is up and the galaxy is upright.  Slightly different color balance, too.  Click the picture to enlarge.

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