As soon as the magnificent Martian opposition of 2020 ended, I thought I would try to shoot some deep-sky objects with my motorized Dobsonian. It was necessary to learn some specific techniques about short exposures, especially in the capturing and pre-processing phase, given the considerable amount of data to process. After some first experiments on M81 and NGC2403 that went definitely wrong, at the end of December 2020 I started shooting an object that is wonderful in visual observation, the Little Dumbbell Nebula, M76. The first time consisted of 20 minutes of Luminance with 1 second exposures. I recognized that it could be done and I was very happy about that. In the meantime the object became less and less observable, but I always had in mind to resume the project, so after a year and many things learned, between the end of December 2021 and January 2022 I dedicated six nights of good conditions to capture the object again. I realized shortly after, that unfortunately the collimation method I was using was not effective so, despite the seeing for my site was good enough, I decided not to go ahead with the processing. In this painful period of horrible weather, I was thinking about which objects I could capture if the weather ever improves (probably never
) and I remebered that exactly one year ago I had imaged M76, and this time I decided to process it despite a not perfect collimation because conditions had been very good. And here is the result.
I hope you like it!
Acquisition: SharpCap
Pre-processing: SiriL
Post-processing Ha and OIII: PixInsight (Crop-DBE-BXT*-Stretch-LHE-NXT**-CT)
*BXT: Sharpen Stars:0.25 - Adjust Star Halos 0.010 - Automatic PSF - Sharpen Non Stellar 0.60
**NXT: Denoise 0.60 - Detail 0.15
Post-processing RGB: PixInsight (Star alignment-DBE-SPCC-BXT***-Stretch-NXT-CT) Photoshop (Wow!Frequency Equalizer Pro2 - Camera Raw-Vibrance)
*BXT: Sharpen Stars:0.30 - Adjust Star Halos 0.030 - Automatic PSF - Sharpen Non Stellar 0.10
Nauris Mirrage 600mm f3,8 -
http://nauris.de/index.php/en/telescopes/vates-astrographParacorr type 2
ASI294MM and ASI294MC
Gain 300 -10°
Astrodon LRGB filters - Astronomik OIII Ha 12nm 2" mounted
Pegasus Astro Falcon Derotator
OIII 10424 best frames over the 15000 captured x 2 sec (340 min ca.)
Ha 5400 best frames over the 8000 captured x 2 sec (180 min ca.)
RGB 1800 ca. best frames over the 2000 captured x 2 sec bin2 (60-60-60 min ca.)
Dark x 100
Volta Mantovana - Italy
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