M33 – Triangulum Galaxy –  09/15/2023 and 09/16/2023

I am tried something a little different here. I wanted to capture data of Messier 33 over a couple of nights to see what I could come up with. Mostly so I can get some post-processing practice in Siril. I collected 1 hour and 45 minutes of 180 second captures on 9/15/2023 and 1 and 1/2 hours of 180 second captures on 9/16/2023 – that is a total of 65 x 180 exposures or 3 hours and 15 minutes of total light collection. I captured 25 x 180 second dark frames and 50 flat frames to use for calibration during processing. SharpCap live stack was running during imaging to monitor progress.

Primary (Imaging) Secondary (Guiding)
Scope: SVBONY SV503 102ED
Filters: UA Field Flattener, SVBONY UV/IR Cut Filter
Camera: ZWO ASI294 MC Pro, Cooled to -5 C
Focuser: ZWO EAF
Mount: Sky Watcher EQ6-R Pro
Scope: SVBONY SV106 60mm Guide Scope
Camera: Orion Star Shooter Autoguider (OSSAG)
Command and Control: KStar/Ekos connecting through INDI Server running on a Libre SBC
Image Processing: Siril

I used the Ekos Polar alignment running it both to the West and then to the East. I was able to get very good polar alignment. Plate solving is calculating the focal length at 700.3 with a focal ratio of F/6.3.

Here is a SharpCap stack of the data captured on 9/15/2023 of 35 x 180 exposures (1 hour and 45 minutes) at 121 gain, 30 offset, and bin 2×2. Darks and flats are applied to the stack. Default histogram stretch in SharpCap is applied to create this image. The original image was resized by 80% to reduce file size.
M33, Triangulum Galaxy, SharpCap Stack of 35 x 180 second exposures. Captured on 9/15/2023

Here is the full 65 x 180 second exposures from 09/15 and 09/16 after processing in Siril. Used the Siril OSC_Preprocessing script to create the master flat, master dark, and initial stack. Background extraction, color correction, and historgram transformation all done with Siril. Once I complete the processing I resized the image to 80%.
M33, Triangulum Galaxy, 65 x 180 sec exposures. Stacked and processed with Siril.
Messier 33 (M33), the Triangulum Galaxy, in the constellation of Triangulum. M33 is spiral galaxy about 2.7 million light years from Earth.

Total Exposures: 65 – 35 on 09/15/2023 and 30 on 09/16/2023
Exposure length: 180 seconds
Gain: 121
Offset: 30
Bin: 2×2

The background is not as black as the SharpCap stack, but the stars are not as saturated. There is a lot more fine detail in M33 itself. I need a bit more practice adjusting the stretch and black levels. Over all I think it looks great, dig the darker dusty details in M33’s disc and arms. The hints of pink and blue within the core. More details moving out from center.

I’ll keep tinkering with it, but I think I am getting a decent handle of the Siril basics, there is still a lot to learn. I did test captures on M101 and M27. Going to run them through Siril to see what I can see. Stay tuned…

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