View Full Version here: : processing the colour of the stars
Somnium
09-05-2015, 11:09 AM
I am having difficulty trying to get the stars in my image of Omega Centauri to have any colour whatsoever. they seem to only come out white no matter what i do. i took 120 second images filtered RGB (camera is a QHY9m, scope F4 10") staked them then combined it in photoshop. my thought is that i have maxed out the wells in my sensor to they are just recording 100% for each colour so there is no way to play with the levels and curves. but should this really happen at 2mins, if that is the case then i will not be able to get deep subs for any image if i still want to maintain colour in the stars. am i missing anything? does anyone have any tricks they use here?
thanks
multiweb
09-05-2015, 03:32 PM
I suspect at 2min exposures you wouldn't saturate the stars so try to stretch the final to a minimum and boost the saturation to the max to get your star profiles right. Then the color will come on its own.
cometcatcher
10-05-2015, 09:08 PM
I always process the stars separately. Generally DSS sucks out the colour so you do have to put it back in somehow. I process in photoshop, select colour range. Select highlights, expand by about 4 and feather by about 2. Wind up the saturation sliders. Also take note of star colour. You may need to balance it. While you have the stars selected, play with some other options like a median or minimum filter. Remember to deselect to work on the rest of the image.
Somnium
12-05-2015, 01:27 PM
thanks for the feedback, i think what was happening is that when i was saving them as Tiff's from FITS liberator it was defaulting the black and white slider in such a way that it was cropping data. i managed to get some colour from the stars but still working on perfecting my processing techniques
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