Can using a Barlow lens increase the size of the image circle for a prime-focus camera in a Cassegrainian OTA with a small baffle tube? E.g. would using a 2X Barlow on a C90 (baffle tube diameter of 15 mm) double the diameter of the image circle to 30 mm (in a 32-mm focuser), to work with a Canon APS-C DSLR camera at prime focus with a reduced resolution of 1080p for video (an effective sensor size of 26 mm)? Or would the image circle still be 15 mm even with the 2X Barlow?
Edited by Nicole Sharp, 04 December 2018 - 07:49 AM.