Common imaging train

WO Flat6AIII + ASI533MC 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. With the 533's T2 ring on, the drawer and a boxed extender close the gap; the small sensor ignores every bore.