ZWO offers a 1-year warranty on the FF65 / 80 / 130 apochromats of the FF series.
The FF65 is a Flatfield Astrograph with an aperture ratio of f/6.4 and a focal length of 416 mm.
Instead of the quadruplet construction of the other ZWO FF apochromats, the FF65 is a quintuplet with two ED lenses, which allows for excellent control of chromatic and other aberrations. With its self-levelling design, the FF65 offers great advantages for astrophotography. It has illumination for full-frame cameras and a fine spot diagram with only tiny distortions of the peripheral stars.
Optical design
Instead of purchasing additional flatteners, calculating the back focus of the flattener or setting the correct distance, you can simply equip this apochromat with various photographic accessories, keep the object in focus and the entire optical system is perfectly set up for shooting.
The FF65 comes with an extendable dew shield, a Vixen/GP finder shoe, a prism rail, tube clamps with handles and various camera adaptors (M48, M54, M68).
The respective back focus applies to these adaptors:
176 mm from M48x0.75 external thread
105 mm from M54x0.75 external thread
130 mm from M68x1 external thread
