The ZWO FF65 is a professional apochromatic flatfield Petzval quintuplet with a focal ratio of f/6.4 and an image circle of 44mm in diameter. The FF65 includes two Extra Low Dispersion glass elements for superb correction of chromatic aberration. The FF65 supports full frame cameras such as the ASI6200, with a central RMS radius of only 2.5 microns.
Differently from standard ED refractors, the FF65 features a Petzval design that does not require to set the sensor to a specific distance to the last lens. That leaves the freedom to use any filter wheel, any off-axis guider or accessory without any worry to calculate the correct distance from the flattener.
With a large 44mm image circle and a focal ratio of f/6.4, this is the perfect astrograph for the advanced astrophotographer. The large rack and pinion 2.5" focuser is natively compatible with the ZWO EAF without additional adapters, and can be rotated 360° to perfectly frame the subject and has a reduction gear of 10:1 for precise focusing.
All the lenses are fully multi-coated and the tube is internally flocked to reduce reflections and absorb stray light. The tube is made of CNC-machined aluminium, the rack and pinion focusing mechanism of brass and the mechanical components are engineered to provide the best rigidity, performance and durability.