The Baader Planetarium Fluorite Flatfield Converter (FFC) is a great accessory for critical high-power lunar and planetary observing as well as any type of projection photography. Designed by one of the APQ optical inventors, the 4 element Fluorite Flatfield Converter covers up to a 6x 7 cm format at magnifications up to 8x. Baader's FFC enables diffraction-limited, apochromatic flat field over a 90 mm circular format. The fluorite lenses protect against any chromatic aberrations or other optical defects to an image.
It is fully multi-coated with a hard seven-layer design. Incorporating a Baader FFC to any telescope or camera results in very high transmission and suppression of stray light. Each optical surface is polished with highest optical standards of 1/10 wave accuracy in order not to disrupt any incoming wavefront from your telescope. The FFC design works equally well on optical systems such as Newtonians, Schmidt-Cassegrains, Ritchey Chretiens, Apochromatic Refractors, etc.