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Old 19-11-2008, 08:17 PM
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QHY8 and color balance

Here's some shot I took with a gray scale card with a QHY8 Gain:1 Offset:60 at prime focus on an ED80. One shot is straight out of the camera, the other is color balanced and finally a snapshot of the RGB ratio I got in CCD Stack. Hopefully this is helpful to other QHY8 users. Blue is the weakest followed by Green. Red is really strong.
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Old 21-11-2008, 07:04 PM
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Sure will be usefull...

Would you say the same ratios would apply if your offset was higher (say Gain: 1 Offset: 116 ?

I do usually find my B channel is rather weak compared to G, and G weak compared to R..

Cheers mate, I'll have a play with this (If ever the skies do clear...)
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Old 23-11-2008, 11:39 AM
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Quote:
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Sure will be usefull...

Would you say the same ratios would apply if your offset was higher (say Gain: 1 Offset: 116 ?

I do usually find my B channel is rather weak compared to G, and G weak compared to R..

Cheers mate, I'll have a play with this (If ever the skies do clear...)
I haven't tried but I did the same thing with a different scope (newtonian)and I got different color ratios again so I'll have to do a bit more testing. Not sure if gain and offset actually affect the color balance. Something to try. I always use very low offset (60) and gain 1.
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Old 23-11-2008, 11:44 AM
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interesting, I generally use gain 1 and offset around 110~116 (still experimenting to find the best settings...

You might get different ratios in a reflector due to the differences in the way the two optical systems focus the wavelengths.. Hard to say.
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Old 23-11-2008, 07:07 PM
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interesting, I generally use gain 1 and offset around 110~116 (still experimenting to find the best settings...

You might get different ratios in a reflector due to the differences in the way the two optical systems focus the wavelengths.. Hard to say.
Here's the ratios I got from a 5" newtonian reflector at prime focus under the same lighting conditions. It's much closer to 1:1:1 than the ED80.
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Old 23-11-2008, 07:52 PM
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coinciding with the hypothesis that the reflectors optical system has less color issues than a refractor... This is to be expected with all but the best refractors I suppose...
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