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Strange decorative error after processing 47 subs with ZWO ASI183MC-Pro

ZWO ASI183MC Background Extraction Processing Artifacts
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Steve Solon avatar
Steve Solon avatar

GREAT CAESAR’S GHOST!

Well, this is new. In all my years, I’ve not seen this type of decorative error before. This is the result of forty-seven 10-minute subs on an 80mm refractor with a ZWO ASI183MC-Pro. Processing in PI: Calibration, Cosmetic Correction, Debayering, Aligning, and Integration. Then cropping, and finally DBE, trying both Division and Subtraction , with this outstanding result. Could my venerable 183 be headed for the river Styx? Would appreciate any suggestions from the assembled astro-throng. Many thanks.📷 M-33 WTH is this.jpgM-33 WTH is this.jpg

  • Dazed and Confused Steve

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wsg avatar
wsg avatar

Was there a bright moon nearby?

Steve Solon avatar
Steve Solon avatar

I’d blame the Moon for anything, but not this time - no Moon nearby. Forgot to mention - there’s also an Antlia Tri-band RGB Ultra filter in the image train.

Mikołaj Wadowski avatar
Mikołaj Wadowski avatar

Looks like something’s gone terribly wrong with the red channel. See how your calibration masters look like and check your registered subs. Do they look normal?

andrea tasselli avatar
andrea tasselli avatar
Newton's Rings, quite possibly. Interference anyway. May be caused by some microlensing effect.
Steve Solon avatar
Steve Solon avatar

Mikołaj Wadowski · Sep 27, 2025, 10:42 PM

Looks like something’s gone terribly wrong with the red channel. See how your calibration masters look like and check your registered subs. Do they look normal?

Hi Mikolaj. Yes, checked all the subs - lights, darks, bias, flats, flat darks. I also debayered by splitting the OSC image into R, G, and B — all look good. Something interesting, though - If I crop the final integration, I get the pattern with DBE; if I don’t, no pattern - I’m still experimenting. Many thanks.

Steve Solon avatar
Steve Solon avatar

andrea tasselli · Sep 27, 2025, 11:01 PM

Newton's Rings, quite possibly. Interference anyway. May be caused by some microlensing effect.

Will check into that, too. Thanks, Andrea.