I have a GSO RC 8in f8 scope. The attached image shows a reflection artefact (from the secondary baffle?) when stretching a composite of a wider image of the Flame nebula with the nearby bright Alnitak star.
Any suggestions for a fix of the cause of this artefact?
I think you will find that a bright star reflection is bouncing off the CCD chip and then reflected back off the CCD glass window and bouncing back onto the chip.
I get this with Alnitak and M45 bright stars as the attached crop shows.
Very annoying and not much that can be done about it. People say that by removing the glass window and re-installing it slighty tilted will fix the problem.
A low reflectivity sensor coverglass like the Astronomik MC Clear will prevent that. I have one in my modded DSLR and get no reflection problems with my RC08.
Thanks Bill and Glen for this advice. I have only had this trouble with
imaging the Flame with Alnitak close by. Alnitak can be nudged off the
direct view but I rather like the dramatic effect of the Flame next to Alnitak.
I guess that the problem could be reduced by taking a lot more shorter
images for stacking and thus reducing the need for heavy stretching of the composite.
The very heavy dew laden skies over Sydney lately are not helping matters either.
Cheers Peter
Thanks Paul
I know that the closeness of the very bright star to the Flame is a big
ask to obtain a good stretched image of the nebula. This is a pretty exceptional case to be avoided where possible. Normally, I have no problems with such bright star artefacts. Pleased to know that it is not
an uncommon experience and not just due to my ineptitude!
Cheers Peter