Image Processing Lesson

Graphic artist Ray Fox on the views_thru_the-eyepiece group suggested
that my original H-a image of NGC 1893 was clipped and that I should
emphasize the midtone ranges. I followed Ray's advice and the result
was impressive. I had thrown away a lot of signal in the original
processing! Thanks Ray!

I think my problem has been that I rely solely on ImagePlus' Digital
Development to process my DSOs, wholly to the exclusion of other
operators. This results in an instantly pleasing image requiring only
a coupe of mouse moves and a second or two total processing time.
Unfortunately, it can also waste a lot of signal!

In my reprocessed image I spent a lot of time and several dozen
iterations in IP's Brightness Levels, Brightness Curves and Brightness
Contrast Stretch (Log). I was quite amazed at all of the nebulosity I
coaxed out of the image stack.

Side-by-side comparisons with histograms at
http://home.att.net/~dpersyk/new.htm

I welcome comments from everyone. Thanks for looking.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL