Hi all, I am hoping someone can tell me what causes this halo around all my deep sky images. I am shooting with an 8" RC telescope with an STF-8300C camera. I process in Maxim, using at least 15 darks and bias to calibrate and I cool to -25 C. First time posting so I am probably missing some vital details. I am happy to reply with any other info needed. Attached image is stack of 23 images, 300 second exposure. Calibrated and auto color converted via stack in Maxim. Unfortunately due to size restrictions the image posted is a small .jpg. I can share the fit files if anyone would like to see them.