The FL55SS has a fluorite element which yields uncompromising optical performance. You will enjoy "a level higher" stunning clear view of the moon and bright planets despite of the range of small aperture, with use of a high-resolution HR eyepiece. The FL55SS turns into a fast F/4.3 Astrograph with the addition of the optical Flattener lens and optional Forcal reducer. It delivers extremely sharp and bright star-field images to the very edge of a full frame imaging sensor.
Unlike ordinary optical glass, the fluorite objective lens works perfectly for suppressing chromatic aberration to undetected levels and makes it bring into sharp focus.
It employs Vixen's dovetail-plate system which allows for attaching to the mount head of AP and SX series of equatorial mounts directly. The mounting block on the bottom of the optical tube has 1/4" and 3/8 screw holes for a camera tripod.
The screw holes on the focuser are applicable to an optional finder bracket shoe for use of a finder scope.