Common imaging train

Askar FRA400C + ASI2600MM Pro + EFW 7×36 + OAG-L

The FRA400C is the compact f/5.6 Petzval: 55 mm behind its M48×0.75 thread, 44 mm image circle. 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. The 44 mm image circle clears APS-C by a wide margin; this one is about the filter shift, nothing else.