Orion Nebula, 2018-12-09

Equipment:
-telescope Sky-Watcher BKP2001
-mount Sky-Watcher EQ6 SynScan Go-To
-coma corrector Baader MPCC
-filter Optolong H-alpha 12 nm
-camera QHY5III178m.
-guider-finderscope 50 mm + camera ZWO 290 MC.
905 frames per 1s.
Calibration at DeepSkyStacker, stacking at Autostakkert, deconvoluton at ImPPG.
Place: Russia, Anapa, backyard.
Scale 50%. At 100% scale – link.

I visited my astronomical friends and took a little shot of the Orion Nebula. I finally took off from a normal telescope, not a photo lens, but I got some troubles in processing. First, with the addition of black spots on the image. The shooting took about 40 minutes (2143 frames), of which 905 best frames were added. 1,200 dark frames were captured. Shooting was guided, but without dithering. It is possible that the lack of dithering and caused the appearance of black spots. There is also an idea that calibration problems appeared due to instability of the camera temperature.

Black spots at image – troubles with calibration

A partial solution to the problem was the calibration in DeepSkyStacker, in which there is a mode of cosmetics – defective pixels are eliminated. At the same time, the image turned out to be more noisy and blurry, but better so than with spots. In the classical calibration, the central part of the nebula was free from artifacts.

Exposure was short, for 1 second, the maximum gain. Visible horizontal stripes began to appear. Help function in Autostakkert – Image Calibration> Row noise correction. A repeating pattern was also found on the masterdark. I will try to install fresh drivers on the camera, but there is a suspicion that this is a problem of the camera itself, because same camera on the same sensor (Meade LPI-G Advanced) haven’t pattern.

Single shot without calibration

I will try to make thermal stabilisation of the camera, I have already ordered a small thermostat. I have a Peltier element, and a heater too. I will not say that I am pleased with the result, but I am glad that I did not have to send all the material to the bin.

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