celestron 6.3 reducer.

[jaygpoo]

Hi, I have a celestron 9.25 scope and a 6.3 reducer . Using my ZWO1600mm with a ZWO   OAG what is the back space required as I can not get the OAG in focus an I have shadows on the corners of my images using the suggested  distance of 105mm   jay

[StarDodger]

3 minutes ago, jaygpoo said:

Hi, I have a celestron 9.25 scope and a 6.3 reducer . Using my ZWO1600mm with a ZWO   OAG what is the back space required as I can not get the OAG in focus an I have shadows on the corners of my images using the suggested  distance of 105mm   jay

That is about the correct distance, and with that Reducer and camera combo you will get some vignetting, which is what you are seeing, use plenty of flats and it will sort it..