Common imaging train

ZWO FF80 APO (native) + ASI2600MM Pro + EFW 7×36 + OAG-L

The FF80 APO is a quadruplet with the flattener built in: ZWO publishes a maximum connection length behind its M48 thread rather than a fixed spacing. The mono train ZWO designed the pieces around: the camera keeps its tilt plate, the 7×36 wheel bolts to it, and the OAG-L bolts to the wheel with its M48 plate facing the telescope. The unmounted 36 mm filter glass still shifts focus slightly, and the 36 mm bore is the thing to watch on anything larger than APS-C. Built-in flattener, so the three ZWO pieces only need to stay under the maximum — and they do, comfortably.