Askar F3.9 Full-frame Focal Reducer for FRA600/5.6

The new Askar FRA400 F3.9 full-frame reducer reduces the effective focal length of the telescope by a factor of 0.7x. The original f/5.6 apo becomes an f/3.9 apo. Its exposure time is significantly shorter, it is reduced to about 50%. The field of view becomes much larger.

The reducer was developed for use with the FRA600 flatfield refractor and offers good correction with this telescope, even when full frame sensors are used. The working distance from the M48x0.75 thread to the camera sensor is 55 mm. The camera adapter is equipped with a 2" filter thread. The reducer can also be used with other flatfield apos from 100 mm aperture, provided that they have the corrector in the tube and not in the focuser.