Imaging Processing Fun with M51 Whirlpool Galaxy

M51

What happens when you spend 3 hours imaging an object only to find that you have only a handful of salvageable images from the session?  That happened to me back on May 3rd when I imaged the Whirlpool Galaxy.  During the night, at some point, I lost guiding and did not catch it so when I went to process the photos I was surprised to see that 2/3 of them were unusable.  Having only 13 images to work with, I processed the images 4 times over to see if I could get a decent image to come out.  Along the way, I learned a ton (as usual).  Here are some of the things I tried and the outcome of each method:

1.  RGB Misaligned – MaximDL RGB Color Combine (Average Method) + LRGB Combining in Photoshop CS6

M51 RGB Misaligned

M51 RGB Misaligned

The image above is a result of the RGB images being misaligned when processing.  Sometimes I get a little impatient and don’t take my time getting everything perfect during the post processing aspect of Astrophotography and this can result in very sloppy images.  When the RGB channels don’t line up, you get a mess of colors scattered throughout the image.  The RGB and the L images were first combined (using the Average method) in MaximDL and then combined in Photoshop CS6.  As you can see, even Photoshop can’t save this image.

2.  LRGB Combination in Photoshop CS6

M51 LRGB Combination in Photoshop CS6

M51 LRGB Combination in Photoshop CS6

The photo above represents an image that was combine using Photoshop CS6.  The stacking of images was done through MaximDL but the separate LRGB files were combined and layered on top of each other via Photoshop.  I did not know how to do this so I searched the abyss of the internet and found this really helpful tutorial on RGB Color Combination in Photoshop.  The end result looked much better than my first attempt but the photo lacks color, which is partly due to only having a handful of color images to work with.  At any rate, the image looked better than its predecessor but I still was not happy with it.

3.  RGB Color Combine with MaximDL (Sigma Clip and Digital Development) + LRGB Combination in Photoshop CS6

M51

This image is as good as it going to get.  Working off of a tip from one my Astrophotography friends, he mentioned that I should stack the images using the Sigma Clip option in MaximDL as it removed a lot of noise from my photos.  For this image, I decided to spend some time aligning the color images in MaximDL to see if the colors came out better than using the Photoshop method.  This really helped as MaximDL brought out some faint color in the image that was missing when I just combined all the of images using Photoshop.  Also, the addition of the Sigma Clip and using the Digital Development feature, I think the image processed this way came out so much better.

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