• Posted on: 14 February 2019
  • By: tihomiry

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

To check the polar alignment of your telescope look trough the polar scope. When turning the Ra axis the polar star should move in the exact circle in the eyepiece without any deviation.

Removing the DSLR build in IR-cut filter will give you at least 50% more sensitivity for hydrogen alpha emissions of the nebulas. Also the camera will be more light sensitive at dark allowing you to shoot more faint objects.

We can check what is like to process day shot with similar to astrophotography techniques. It is cloudy in Bulgaria for the next week or so and I took shots of the nearby mountain trough the fog with 200mm lens.

Most of the modern LED backlight screens including Laptops, TV and smart phones use PAM technique for Pulse-amplitude modulation. This means that they switch on and off state very rapidly.

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