[dugnsuz (Doug)]

Originally Posted by avandonk

Doug generally internal reflections in lenses occur from bright stars the same distance away from center as the star that caused it. The center star in your image is sitting on its own reflection. Sigma Orionis is causing the reflection at the left. The other is caused by Anilam the central star in Orions belt. Even with the best antireflection coatings a tiny amount of reflection from a very bright star is quite noticeable.

Bert

Cheers Bert,
Makes sense - the half moon seems an unlikely suspect now as it would have been in completely different places in the sky at the start and end of the imaging session, but the reflection remains at a constant spot on all the subs. These reflectons are a first for me - or at least I haven't noticed them before! Thanks for helping to clear that up.
Doug