Common imaging train

Askar 107PHQ + ASI6200MM Pro + EFW 7×2" + OAG-L

The 107PHQ quintuplet is flat-field by design with a comparatively short maximum connection length — long trains run out of focuser. 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 three-piece ZWO train fits under the maximum with focuser travel to spare; the tool shows exactly how much.