Common imaging train

WO Flat6AIII + ASI294MC Pro + filter drawer

The Flat6AIII is adjustable: dial its helical ring to William Optics' per-telescope figure and build the standard 55 mm behind the M48×0.75 T-mount thread. 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 294 wears the 11 mm T2 ring like the 533; its 23 mm diagonal is still safe through the drawer's M42 output.