Help with odd artifacts in amages

[pmrid]

I've been working my way into OSC imaging using different SharpStar 94EDPH and 61EDPH APO refractors and Optalong L-Enhance and L-Extreme filters.

I'm finding these odd artifacts in my images and can't put my finger on a cause.

They are basically rings around star cores - and they are across the whole image although more prononced in the edges and corners. I've encountered them using Flattener/Reducers and without.

I am using ZWO filter cartriges/drawers and I've tried moving them up and down the backfocus 55mm space but wth no difference.

I focus with ASIair Plus and with a Bahtinov mask with no difference.

Exposures have been 180and 300 seconds with no appreciable differnce.

A couple of extreme crops attached as examples.


Any thoughts?

[ronson]

Hi Peter,

What camera are you using and what camera settings in Asiair?

What software are you using to develop the FITS files?

[pmrid]

Using both ASI533MC Pro and ASI071MC Pro CDs with gain set at their Unity Gain points - 94 in each case. Stacked in DSS and saved as 32 bit Tiff images processed in PS6.

[RobC]

Morning Peter,

They look like stacking artifacts to me. Suggest you restack in PixInsight.

Cheers

Rob

[pmrid]

Thanks Rob. I’m going to give Siril a whirl. I’m a PI luddite I’m embarassed to admit.

[Nikolas]

Turn off cosmetic correction in the DSS settings those donuts are a tell tale sign they are turned on

[pmrid]

Thanks for that tip. Will check that ASAP.