William Optics Flattener dedicated to the Zenithstar 61 optical tube ensures the maintenance of uniform image quality - flatness, because the flattener is a "flattener" - both in the center and on the edge of the frame, eliminating the negative influence of the refractor's optical system, which as you move away from the center of the frame, the sharpness of recorded objects gradually deteriorates.
This flattener does not change the effective focal length (it has a multiple of 1x).
• M4 / 3
• Sony A
• times: 1x
• back focus: 67.7 mm (for M48) / 69.2 mm (for M54)
• correction distance for SLR and mirrorless cameras: 1 mm
• telescope mount: M54 thread
• camera mount: M48 thread
• possibility of mounting the filter: yes, thread M48
Product page on the manufacturer's website: https://williamoptics.com/new-adjustable-flat61-for-z61
• flattener for Zenithstar 61 refractor with 1x multiplicity