RGB aberration


Cross posting.
This is not something I have seen before but, does anyone know what this is?
It started in panel 2 of a 3 panel mosaic and appeared on the right edge of all the RGB subs.
By panel 3 it was gone.

I was wondering if it is some type of reflection off my QSI OAG ?





That’s a reflection from a nearby bright star that is just off the edge
of panel 2. The star is then included in the main body of panel 3,
which is why it doesn’t appear there. The only way to fix this is to
redraw the mosaic such that the offending star is either just inside the
frame of the panel, or well outside of it.


You don’t say what image processing tools you are using but when combining panels with Pixinsight,
this problem can be fixed by looking for bright stars near the edge of the panel and using the drawing tool to erase the star with black. When the panels are combined that star will be supplied by the overlapped image and the artifact will be gone. The same method likely applies to other tools.


Desertsky, this is not an aberration caused by combining the panels in PI.
The artifact is present on all of the subs in panel 2. Cropping out the
offending star will not remove the reflection lines caused by the star in
the first place.


The source of the artifact might be different but the solution still works if there is enough overlap. It might be possible to crop that out in panel 2 or as I said erase it with black so that it does not appear in the combination.


Yes, you are right, but in this case the panels would have to overlap by a
huge amount and I don’t think that is the case. I know it stinks to have
to reshoot data but getting rid of the source of the problem is better
overall for the image. I’ve had to do that a few times in exactly the same
case as this. It’s just very hard in my experience to get rid of a major
artifact like that.


Thank you all
It was Alnitak, my overlap was 20% so I may play with the drawing tool and become familiar with it.
No matter panel 3 needed a re shoot anyway and the entire project begs for 6 panels to look decent.

Live and Learn

Thanks again