The William Optics Flat73A is an apochromatic 1x field flattener for the Zenithstar 73. The 43mm image circle makes it a perfect match for full-frame sensors.
The Flat73A features adjustable spacing for use with a range of cameras and imaging systems. The Flat73A includes an M48 filter thread which will hold any standard 2" mounted filter. It also includes a handy camera rotator for precise framing of targets.
Compatible with William Optics Z73 which has an M63 x 1 thread. On the camera side there is an M48 x 0.75 male thread, which will accept any wide T-ring (sold separately).
Note: As this is an adjustable flattener, you must adjust the distance for your specific telescope. See the Instructions tab above.
|Reduction factor||1.0 x|
|Telescope connection||M63 x 1|
|Camera connection||M48 x 0.75|
|Image circle||43 mm
|Backfocus distance||55 mm + 11.2 mm adjustment from rear section of flattener|
Note: Once you have unscrewed the rear adapter to the appropriate value in the table below, the remaining backfocus distance to make up will be 55mm from the rear M48 thread.
Distance adjustment needed for correct backfocus