I am testing the combination of old version of William Optics F6A 0.8x focal reducer / flattener on my GSO 8RC. To my surprise, it seems to be working well:
Just 35x10min Baader H-alpha / QHY 163M, stack / simple MLT denoise and stretch / curve adjusted. Not much being done yet as I am testing the setup. The backfocus from the flange of focal reducer is ~62/63 mm.
The pixel scale is 0.603 arcsec/pixel, which is exactly 0.8x from 1607mm focal length of my setup.
Comments are welcome.
Edited by Edmond S., 17 October 2021 - 10:09 AM.