recently i captured C/2022 E3 (ZTF), using a telephoto lens (Tamron 35-150mm F2-2.8 Di III VXD), my Sony A7iii, and a star tracker.
Instead of the lens hood, i just had a dew heater wrapped around the lens.
Nearby, there were some wind turbines, and they're marked by those red position lights. Between one of those and the direction of my observation, there was an angle of roughly 90° or more. So one possible explanation would be, this red light entered the lens due to the missing lens hood, did some internal reflections and scattering, and produced those fringes.
However, those fringes look isotropic to me, and also not very red. It could be some issue with AR coating within the lens stack
I also captured my dark frames there. My flats (and the flatdarks) i captured against a white wall during daylight i admit. They don't show those fringes (but other artifacts instead).
Actually i'm trying to build a model of those fringes, and then substract them. They're not centered exactly in the very image center, and i have to guess by eye.
If anybody has some experience about how those artifacts are caused, and how to avoid them - comments very appreciated.
Also, if there is any good idea of how to get rid of those <-- you can be a hero!
CS Horst
Attachments:
Top - Stack of comet-registered subs
Bottom - Stack of star-aligned subs
