Glad it helped!cytan299 wrote:Hi Ivo,
Thanks a lot for looking at my data. It helped a lot!
It's possible the noise is still due to contribution of light pollution. Light pollution is becoming increasingly difficult to filter out with the switch to LED street lighting.
You should never color-calibrate a processed (stretched) image! It doesn't make sense mathematically; your data should still be linear (unless you're processing and color calibraring in StarTools).
As you can see, using something like eXcalibrator on data acquired with a light pollution filter yields far worse results than attempting to color-calibrate by known processes;
Spiral galaxies like these should exhibit a yellowish core, bluer outer rims, red/brown dust lanes and pink/purple H II areas dotted around their arms. A light pollution filter tends to kill yellow, but blue and red/orange should remain largely intact.
Stars should not be uniformly white, but should exhibit coloring according to the black-body temperature curve. With a light pollution filter, yellow will usually be absent. So at the very least, you should have red, orange and blue stars in your image.
It's worth investigating why your stars are purple. Something in your imaging train might be this causing color fringing? The FSQ-106ED is an excellent instrument and should not exhibit this sort of color fringing. Is there any other glass in between your OSC and your scope, except for your light pollution filter?
AutoDev usually does a good job with any sort of reasonable signal. It will definitely struggle however if any "real" detail stands out of the noise only marginally, like in this case. If you cannot get AutoDev to tone down the noisy background by specifying an Region of Interest and using Ignore Fine Detail parameter), a manual Develop may indeed be much easier to deal with.Another question that I have is when do I use manual Develop rather than AutoDevelop? I've always used AutoDevelop and like you saw, it didn't work very well. So, is it better to try Develop first before using AutoDevelop and just try both and see?