
William Optics FLAT6AIII Adjustable Field Flattener
The William Optics Adjustable Field Flattener improves the flat-field imaging performance of William Optics GT71, GT81, Z81, and Z103 refractors. Features of the William Optics Adjustable Field Flattener APO triplet optics made with Ohara glass. Fully multi-coated to provide bright and flat field across 97% of full-frame sensors. Built with M63 threads on the telescope side. The following telescope models can be used with the William Optics FLAT6AIII Adjustable Field Flattener Amount of Adjustment: GT71 - 9.1mm GT71 - 9.1mm GT81 - 7.1mm Z103 - 2.5mm Z81 - 5.2mm Back Focus: GT71 - 64.1mm GT71 - 9.1mm GT81 - 62.1mm Z103 - 57.5mm Z81 - 60.2mm Image Circle: GT71 - 44mm GT71 - 9.1mm GT81 - 44mm Z103 - 43mm Z81 - 44mm Refine your flat-field performance. Fully multi-coated Ohara glass optics. Reducing factor: 0.8X.