A good mate kindly gave me a Bintel 8 inch f4 Newtonian and rings to go with it. Goes great on my ancient AOS Sampson mount. Has a really nice 2 inch focuser too. Put the EOS Ra on it with Baader MPCC and Baader UHCS filter to test it out on the Seagull Nebula. I think the old MPCC is meant to work best at f4.5 but happy with it at f4 with a full frame sensor. Only very slight coma at the corners.
Full size image available here
https://www.astrobin.com/qq5gcw/
Had to wait ages to use the scope as we've had so much cloudy weather. Not done much imagingbthis summer as a result.
Scott