Hey ho, I have a new ccd cam (QSI) with 1.25" filters in internal filter wheel. Tonight was taking flats on Tak TSA 120 with optec focuser (>2" focuser) using camera's 2" adaptor. And I wondered why my flats all looked like a globular cluster! Central portion lovely and illuminated, but that's it.
So apart from using a 1.25" adaptor, what can I do about it?
Graham
