Askar F/3.9 focal reducer for FRA400 and FRA500

Askar F/3.9 focal reducer for FRA400 and FRA500

Askar provides a brand-new F3.9 full frame reducer for the FRA400/5.6 and FRA500/5.6 astrographs, further reducing the focal length and thus shortening the exposure time on its original focal length and f/5.6 focal ratio design basis. The reduction factor is 0.7×, and the reduced focal length is 280 mm (FRA400) or 350 mm (FRA500), which can satisfy most deep-sky astrophotography. The back focus is standard 55mm. The reducer has built-in M48×0.75 thread, easy for the attachment of 2" filters.