Askar 120 APO + 0.8 reducer Full frame coverage (Nikon 800E)

[fwm891]

Managed to fit my Nikon 800E to the Askar 120 APO with its 0.8x reducer also fitted. Shot a number of subjects but I've just picked one 90 second sub from a set of M45 to process this morning.

It was apparent last night when imaging with the 800E that the throat/lens mounting flange was acting to mask the extremities all round especially the corners. Stars are still visible in these areas so perhaps I should shoot some flats and try to reduce the shadowing caused by the cameras lens mounting.

No problems with smaller APS-C formats.

Processing in PI, noise reduction only.

NGC2264 image added (6x 90 second subs) processed as above

Edited March 4 by fwm891
Image added

[vmh104]

I'm a little confused by the straight edge vignetting at the long borders. That must be caused by something else?