I'm new to astronomy, and am looking to buy my first telescope. I'm primarily interested in planetary astrophotography, but want something that's good for viewing as well (for my boys). Based on some posts in the Cloudy Nights forums it seems like Celestron's EdgeHD series would be a good choice.
From a Celestron white paper (and an answer to a question on their website) it seems that all the EdgeHD scopes have a 42mm image circle. I currently have a Sony a65 with an APS-C sensor which I plan to use, so that's fine. However, I plan to update to a Sony a7r ii or a7r iii which have full frame sensors, so that's a 43+ mm diagonal sensor.
Celestron markets their EdgeHD 9.25" and larger scopes as being appropriate for full frame sensors, and they also advertise their M48 T-adapter as producing "better illumination for today's larger full-frame imaging sensors, all the way to the corners". It seems to me though that if your image circle is smaller than your sensor, you will have vignetting no matter how large a diameter the T-adapter is, and the M48 size will not improve illumination at the corners. Am I missing something?
Thanks for any insights,