Common imaging train

Askar SQA55 + ASI6200MM Pro + EFW 7×2" + OAG-L

The SQA55 is a 55 mm f/4.8 Petzval with a 44 mm image circle; Askar quotes a connection range with 55 mm recommended, measured behind its M48×0.75 rear adapter. Full-frame mono: ZWO only recommends 2" wheels for the 43 mm diagonal, the camera wears its M54 tilt plate, and the wheel and OAG-L bolt on with screws rather than threads. Every bore in this train has to clear the diagonal. The 43 mm full-frame diagonal only just fits the stated image circle — expect the corners to show it.