Posted: Thu Nov 19, 2015 10:48 am
I was recently asked what was wrong with an image with halos around bright stars. The image taker thought the field flattener was causing it. Usually they are caused by reflections from the light pollution filter. Some filters are worse than others. Some more expensive brands claim to be halo free. The halos in my image below came from a CLS filter. They are a nuisance but Photoshop can reduce them down - sorry Pixinsight users.