Artefacts around large stars - peoples thoughts

[Hughsie]

Please see attached a close up of an image in the SHO palette.

If you examine the larger stars you will see two points of lights positioned at the 2 o’ clock and 8 o’ clock orientations and this is consistent for each large star. Although the image is a combination of Sii, Ha and Oiii, these artefacts only appear in the images produced using the Ha filter (Baader 7nm 1.25” filter).

At first I thought it was hot pixels but then this would be a random distribution across the image whereas these appear to be associated with larger stars in a specific orientation suggesting a ‘mechanical’ issue.

The image is taken using a William Optics Z103ED refractor with a Flat 6AII reducer attached using a ZWO ASI1600mm Pro Cooled camera.

I have done some research online and can’t seem to find any mention of this type of artefact and was wondering if anyone else has experienced this before?

Thank you in advance,

John

 

 

Edited September 16, 2019 by Hughsie

[wimvb]

My guess is that it's the onset of microlens diffraction. If you image brighter stars it will show more clearly.