Below is an stack of six 10 minute Ha images taken with a Planewave CDK 12.5 scope under a bright moon. Severe reflections are evident. A similar O3 stack taken in the same run were nearly perfect. Both are Chroma filters. This would seem to point at the Ha filter which have used without problems on another scope. Could the bright moon be causing this or something else?
📷 cdk 12.5 Ha filter reflections.jpg
It’s a micro-lensing effect and the Moon or the scope isn’t culpable. AFAIK you can’t avoid it with a bright star in the field. Well, unless you mask the sensor but I guess this isn’t pratical…
Hi.
If you get nearly perfect OIII images in the same conditions I suggest to check if the Ha filter is mounted correctly. Maybe you accidentally put the filter upside down and the antireflection coutings are placed opposite to sensor.
Regards, m.
Planewave recommended extending the baffle tube in some cases to block external light from the optical path. Worth investigating as well.