Hi all,
I recently picked up the optolong para 2 inch filter (10nm NBF). I run it on a Askar 65phq (F6.4) and ASI2600mc camera. The flats appear very abnormal in that there is a large dark area on one side. Curiously, my target seems to have less stars on one side. I’m going to shoot the same target tonight with my other NBF, a SVB220 (7nm NBF). But the flats on it are a lot more homogenous. Looking to see if weird looking flats is normal for the Optolong para, or if I possible got a bad filter. Thanks ahead of time.
screen shot of the flat: Flat 1 example.jpg
autostretch of the stacked fits: Screenshot 2025-11-03 161814.jpg
