Common imaging train

Askar 65PHQ + ASI2600MC Pro + filter drawer

The 65PHQ quintuplet needs no flattener: Askar publishes a maximum connection length behind its M48 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. No flattener and no fixed spacing: the drawer and camera just have to stay under the maximum.