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Old 18-08-2009, 10:21 PM
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RobF (Rob)
Mostly harmless...

RobF is offline
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,625
Its one of those things experienced astrophotographers make look so easy that I suspect is actually quite hard for many of us.

Some suggestions:
- use lower ISO (400 or 800) as suggested to avoid burn out
- isolate (mask) and copy stars early on in processing, so can manipulate and combine and mix back in later
- you need to boost the colour saturation to get the colours you're after, however doing this across the entire picture often accentuates chromatic noise in the background of the image to unacceptable levels
- image from dark sky site with no pollution filter (and no sky gradient)

For quick and dirty in Photoshop:
- Select/Color Range/select:Shadows, tick "invert" box
- Select/Modify/Expand = 2
- Select/Feather = 2
- Image/Adjustments/Hue/Saturation - boost Saturation slider

You need to have the color balance, black points, etc set close to final balanced values for this to work - if you have too much blue or whatever showing at this point, all your stars will come out with that color accentuated - just undo, go back and tweak colour balance, then have a go again as per above.
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