Common imaging train

Sky-Watcher Esprit 80 flattener + ASI533MC Pro + filter drawer

The Esprit 80 flattener is 55 mm from its mating surface behind an M48 thread, with a 33 mm image circle that is tight even on APS-C. One-shot colour usually runs a single dual-band filter in a drop-in drawer instead of a wheel. The M42 drawer threads straight onto the camera and leaves a gap that one of the extenders in the camera box closes — once the filter glass is accounted for. The 33 mm image circle is small, which makes the 16 mm-diagonal 533 a natural match.