M33

 Posted: Jan 24th, 2026
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NGC
IC
HD
Technical Info
Telescope/Lens: Sky-Watcher 72ED evostar
Camera: ZWO ASI183 MC PRO
Mount: HEQ5 Pro (Rowan belt modification)
Guide Scope: Sky-Watcher 72ED Evostar - Askar OAG-M54
Guide Camera: ZWO ASI120MM mini
Software: ZWO ASIStudio 1.17.0; GraXpert 3.1.0 rc2; Siril 1.4.0; Affinity Photo 2.6.5
Accessories: ASIAIR PRO; Field Flattener 2"; ZWO EAF; ZWO Filter Wheel mini;
Exposure:
40 x 300" ISO/Gain: 111 - Lights
Green, Bortle 4 zone:
 Ansião, Portugal
 Oct 11th, 2025
3 h 20 m
89
Resolution: 4095x2852 px
Scale: 9989 KB

Taken on 11/10/2025, processed on 19/01/2026

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Comments

The total accumulation time is incorrect.
Don't add information on dark, flat and bias to the image description!
And why there are no colors on the image?
29 Jan, 2026 Reply
Paulof Replied to Yas
1- You are absolutely right about the number of frames, as 51 was a typo... now it's corrected (40x300s)
2- Information on Dark, Flats and Bias deleted, but I'm a bit surprised as in all the sites I post, like Telescopius.com, for example, that is a useful info for colleague astrophotographers...not in here... ok, is that a site rule, or just your opinion ?
3- No colors ? check again !!
5 Feb, 2026 Reply
Yas Replied to Paulof
2. There is no site rules on this, but Astrobin site also don't use these info. Bias, Dark, Flat are need for preprocessing and I don't see how it could be useful. Not only that, but modern cooled CMOS cameras have very low thermal noise, so using dark frames, especially when there are only a few of them, can even add noise to the final image compared to simply subtracting the average dark frame value.
3. The colors are still not very noticeable. If you can share the original image (the final sum after calibration), I would try to process it.

Translated with DeepL.com (free version)
5 Feb, 2026 Reply
Paulof Replied to Yas
2- My camera is an ASI183MC PRO, which has Amp Glow, and with no Darks, no way to get ruid of the Amp Glow !! Unfortunately, I've no funds to buy another camera, so this one has to stick around...
Flats and Bias are mandatory to use anyway, so the matter is just if we declare them or not... got it !
3- The colors are the ones my camera captured without enhancing them artifitially in processing.
5 Feb, 2026 Reply
Paulof Replied to Paulof
Besides that M33 is not a very colorful subject anyway.
You can check the colors of a few of my other images showing more colorful DSOs. So it's not the camera nor the processing. Is the subject
5 Feb, 2026 Reply

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