I am hoping that someone may be able to explain what is happening here?
I have attached an image – which I have processed to exaggerate the circular banding that I have started to notice in my images.
This image was taken with an 8” SCT with a Meade f6.3 focal reducer / field flattener. It is a stack of 30 x 3min @ ISO400. Darks, flats and bias were applied.
I would like to know if there is something wrong with my setup?
Can anyone help or offer suggestions?