Common imaging train

Starizona Apex ED 0.65× + ASI533MC Pro

The Starizona Apex ED 0.65× is one of the few reducers with a T2 (M42) output, which is why it pairs so simply with a T-ring or a T2-fronted camera — and why its 30 mm image circle suits small sensors. Nothing between flattener and camera: the simplest train, and the one where the extenders ZWO ships in the box are meant to land exactly on the target. T2 to T2 with no adapter: one thread standard end to end, and the gap is a plain stock-ring sum.