I apologize for posting a problem I've seen here many time on the subjects of light leaks with a newtonian scope. I've read all the post on this subject. I've remedied all the possible issues. I've examined every possible cause but I'm all out of ideas. A wicked gradient in all my images with my new ASi 2600mm and 8" newt in every image. You're my last hope of finding where this is coming from. Here's what I know:
Scope and camera have been thoroughly inspected and masked for every possible light leak from the back of the primary mirror to the end of the focuser. Visual inspection of inside the ota is jet black with only the primary and secondary visible. Absolutely no extraneous light visible from anywhere.
Dark frames look perfect, no bright areas at all. Same with flats, perfect. Calibration is working as its supposed to meaning all vignetting and dust are corrected. Image looks good except for the severe, stray light that's always in the same spot, and runs at the same angle in all my images.
I have one image for an example. The obvious issue is exactly the same in every image I take. This image is 5 minute Ha subs. Shorter RGB subs show similar results but interestingly I'll get a red streak, green streak and blue streak instead of one color streak of light.
Thanks for your thoughts