OIII Aberration Question

Askar FRA500 Acquisition OIII Deep Sky Artifacts
2 replies•160 views
Ollie Aplin avatar
Ollie Aplin avatar
Hi AstroBin hive mind,

Question for you all.  I've been imaging the Flying Bat and OU4 from the UK in 'nautical' night/twilight (yes I know, ill advised!) and I'm getting the below aberration on this bright-ish star (think it is HD 202830 +9 Mag) in my cropped OIII stack.  Image is 36x600s OIII with the FRA500 @ f/3.9 and I've been really strict in only selecting the very 'best' frames I can get right now (via SFS) which is about 1hr per night.  Filter is the Optolong 3nm OIII, there is a very small amount of tilt in the system but the target is centred on the chip.

I'm thinking this is a 'halo' albeit not predominantly circular, or a reflection artefact.  Are certain types of stars more prone to this?  The two central ones seem of similar magnitude visually however I think the other central star is actually brighter in reality.  Just keen to know any advice on its source and reducing this, shorter subs?  Have I reached a limitation of the filter imaging 600s @ f/3.9?

Any feedback welcome.

Thanks,

Ollie

Helpful Respectful Engaging
Ollie Aplin avatar
Ollie Aplin avatar
Star is actually HD 202380, not 83, is Mag +6.6 and is a red supergiant, perhaps a factor in OIII filter performance generally?...  As an aside, I don't intend to use the NB stars but artefacts are unfortunately left behind by StarX.

Thanks!
andrea tasselli avatar
andrea tasselli avatar
I think you should test Starnet++ V2 at the linear stage as it often outperforms SX on residuals. As for avoiding it these artefacts are usually strongly affected by incidence angle so try to move the frame a bit.
Related discussions
Does anyone know what this aberration is from?
Hi Everyone, I've been dealing with this aberration for some time now and can't seem to figure it out. This is taken with an ASI6200MM with OAG, filter wheel and Chroma filters. I get the same aberration for a particular target regardless of ...
Directly addresses optical aberrations in stacked deep-sky images from astrophotography.
Nov 13, 2024
Is this an acceptable noise level?
Hello everyone, I'm looking for a bit of advice on whether or not the level of noise I'm seeing in my images is too much or not. I've recently been going after IC-63 (Ghost of Cassiopeia) and I've tried to push on the Hydrogen-alpha i...
Discusses image quality assessment including noise in stacked astronomical observations.
Apr 12, 2025
Deep Sky Stacker: Getting the Most Out of It
DeepSkyStacker (DSS), a fantastic tool for astrophotographers. I've been using it for a while now, and while it's incredibly powerful, I've also run into a few quirks and challenges along the way. Do you still think that this stacking sof...
Covers stacking software optimization relevant to processing deep-sky imaging data.
Nov 12, 2024