HD199956 (dust ripples or optical anomaly?) | Astrobiscuit | Page 1

foggy mortar Sep 7, 2025, 10:48 PM

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Cropped in on HD199956 from my Ha image of the Cygnus Wall. None of my other images with bright stars have these ripples. Can anyone confirm what these ripples are? I've read about these around Wolf- Rayet stars but this isn't one. I used my 130PDS, Svbony 5nm filter and the ASI585MM Pro.

sleek galleon Sep 7, 2025, 11:00 PM

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it's an optical thing. I'm not sure the exact reason for them. They're newton rings basically.

foggy mortar Sep 7, 2025, 11:03 PM

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Thanks for the info. I just haven't seen them on my other images, but this is a really bright star.

knotty valley Sep 7, 2025, 11:08 PM

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just diffraction rings

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light wave interference passing through the aperture

waxen tapir Sep 10, 2025, 3:42 AM

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There are 2 phenomena happening at the same time. Airy discs which form when ligh passes trough a circular aperture and CO modulation rings that are formed when the light is difracting around an object, in this case the central obstruction of your telescope.

#HD199956 (dust ripples or optical anomaly?)