Calibrating with Stars

[twade]

To all,

I derived new weighting values for my setup using two calibration stars.

F8IV: 0.84:1.00:1.79

Since PixInsight Standard does not allow values greater than 1.0 in the LRGBCombination, I had to change the weights to 0.47:0.56:1.00.  Here's the result,



Here's the resulting histogram,



Is it common to get such an unnaturally colored background (i.e. way too blue) when trying to color balance using stars?.  I'm just starting to derive RGB images so I'm not sure if this is common or not.

G2IV: 0.95:1.00:1.59

These values were changed to 0.60:0.63:1.00 in RGBCombination due to the reason mentioned above.  Here's the result,



Here's the resulting histogram,



Again, the background is too blue.  Basically, I'm forced to neutralize the background using a HistogramTransform which invariably will destroy the G2IV or F8IV "color balance".

Is there a better way to do this?  Am I doing something wrong?

Any comments or suggestions would be greatly appreciated.

Thanks,

Wade

[Jack Harvey]

As per the other thread a few guys in our group swear by G2V and get good results and others ignore them and get good results with image color.  I am in the ignore and rely on setting proper black points, doing careful white point and gamma adjustment and rarely tweak any colors at the end of processing.  That said I occasionally have to deal with a gradient or may see a little too much green in the image that I remove.  In the end I rely on a calibrated monitor screen and my eye (as well as others who may look at the image).

[twade]

Jack,

Thanks for you input.  

As stated on the other G2V thread, perhaps the best thing to do is just neutralize the background and let all the other colors fall into place.

Wade

[Jack Harvey]

I think Stan Moore summed this dilemma up well and I included his comment in the other thread.  It is kind of my philosophy on this.

The ratios are sensitive to sky conditions, especially sky-alt (lower alt extinguishes blue much faster than red). I really don't put much faith in rigid ratios. Feel free to balance each image for the most pleasing hues. There is no such thing as "true color"! <g>