This incredible Orion neighbourhood is always fun to image! It has been 3 years since 2018 so I gave it a try again. Unfortunately clouds have been very persistent, only 4 hours of data was captured. Nice to compare with the two previous attempts with the Esprit120 (December 2018) and with the C11 (March 2018)
A final processing of M81 and M82. This includes over 20 hours of RGBHa data, taken on different nights in March and April with the Esprit 120mm and the ASI183MM. I found 300 second subs at gain 111 would burn out most stars, leaving no color information anymore. Therefore I used the 300s subs as luminance channel, but in APP using only 50% of it’s luminosity (RGB Tool). On additional nights I captured 120s subs RGB with Gain 111. That’s still a high gain for the ASI183MM, resulting in burned stars, loosing there color, but somehow managed to get that processed in the right direction. The H-Alfa channel was obtained by 600 second-subs at gain 200 (35).
After cleaning & collimation, I tested the C11 with the Starizona F 7.2 reducer, the ASI183mm (way oversampled obviously), and guiding using a simple external 8×50 guider and the ASI290MC. Just as a test not bad. I’m not convinced the mirror shift did not have influence in this image. Focusing was a pain, needed to be done manually.