Stars all seem saturated?

[topboxman]

Hi Terry,

Thanks for the compliments.

There are several ways to run Color Calibration. In your case, I created a preview around unsaturated stars at upper left part of your image for White Reference. Then I made sure to check "Structure Detection" check box of CC tool which means to only look for unsaturated stars inside the preview. For background reference, I created another preview on a very small dark spot. This preview does not need to be large. I used the same background reference preview for BN.

CT Sat means Curves Transformation using "S" tool (lower right of CT) and I believe "S" means Saturation.

Your sub-exposure times of 5 minutes should be fine. I am not sure why I couldn't bring enough nebulosity. I will have to go back and see if I can re-process it better without affecting star colors. CC really made a difference. Before CC, the Histogram showed color imbalance and after CC, the color got well balanced.

Using my scope with new laptop tonight was a bust. Suddenly high clouds rolled over about 30 minutes before astronomical darkness. 

Peter

[Terry Danks]

Thanks, Peter for this assistance in getting some star colours.
Roger on the "CT sat", too.
My image has already improved about 1000% over the initial effort, see the attached HaRGB using Silvercup's script. I will have another go with CC though too see if I can get a little more reds into the RGs. I can see some red at 100% size, but I'd like more.

Sorry you got clouded out last night. Weather is perhaps the greatest of our frustrations in this pursuit!

Terry

[topboxman]

Hi Terry,

Much better!! It takes some time to get the hang of using PixInsight.

Adding Ha can give a nice boost to RGB image. Silvercup's script makes it easy to use. The script got expanded to add other NB like Oiii and Sii to RGB.

Peter

[topboxman]

Terry,

When I opened each of Red, Green and Blue files you uploaded, they show three different images. They are image integrated file, low rejection map and high rejection map. I looked at the rejection maps and they show quite a bit of rejections including stars and some nebula. If you use Winsorized Sigma Clipping for Image Integration, what Standard Deviation numbers are you using? I usually use 5.0 for both Sigma Low and High. I think the larger the number the smaller the rejection.

It's possible the Image Integration may have robbed some useful signals that could have affected nebula and star colors. Try play with different Sigma Low and High for Image Integration.

Peter