> COLOR RESTORATION AFTER RAW FILES STACK IN 16 BITS
If you have used DeepSky stacker to stack RAW files, maybe you have notice that the resulting image is poor of color saturation. This is because it has a higher number of bits then the display could show. Going to less bits per Chanel we are loosing information so it is good idea to do any touches as early as possible. DeepSky stacker give us tool to achieve correct color balance and increase luminosity and saturation. The best color balanced image has all the 3 channel (RGB) histograms overlapped. You can adjust this as well as increase intensity of high lights and shadows (correct the background). Finally use the saturation slider to achieve the colors. But be careful with the color noise.
Below: NGC 7635 Bubble Nebula 06.09.2015. Pentax k-5, 30 frames x 30s. ISO 51200. UHC-S Oxygen III and Hydrogen alpha pass filter. Telescope SW 200pds, F1000mm 1:5. The “bubble” is created by the stellar wind from a massive hot young central star. At the upper left M52 Open Cluster. At the upper right – upcoming cloud
Recently I got one very good lens the Asahi Takumar 135mm 1:2.5. This is fast telephoto lens and from my point of view a good lens should be with aperture from 1:1,2 to 1:2,8.
Moon at 45% illumination and 70x magnification. With aperture of 200mm,14,1 stops dynamic range, color depth of 23.7 bits at this image there are slight color variation on the moon surface that reveals it’s structure.
This is the beginning of my research on how dark the sky could be and what is benefit of a dark sky for astrophotography. I was inspired from those 2 sites. First one presents mathematical model of how dark the sky is.
You can find my last DSLR Astrophotography article in Bulgarian at page 76. I am sharing my last findings for this publication, Specially written for the Institute of Astronomy.
Satellites, cosmic trash or UFOs, the moving spots are everywhere on the sky. Typical satellite behavior is to reflect sun light. It should be yellow or white and could fade and shine due to its rotation.