Askar 131F Quadruplet Flat-Field APO - ASKAR-131F

Specifications Parameters Aperture size 131mm Focal length 983mm Focal ratio f/7.5 Objective lens Quadruplet air-spaced APO(including one ED glass) Image circle 44mm Maximum accessory connection (with the focuser fully retreated) Imaging mode: 73mm (from the base of M48×0.75 male thread） 91mm（from the base of M54×0.75 male thread) Observing mode: 131mm（from the end of 1.25" eyepiece holder） 141mm（from the end of 2" eyepiece holder） Minimum accessory connection (with the focuser fully extended) Imaging mode: 43mm (from the base of M48×0.75 male thread） 61mm（from the base of M54×0.75 male thread) Observing mode: 101mm（from the end of 1.25" eyepiece holder） 111mm（from the end of 2" eyepiece holder） Total length 878mm(including 1.25" adapter as dew shield contracted） 963mm(including 1.25" adapter as dew shield fully stretched） 941mm(including the photographic adapter as dew shield contracted） 1026mm(including the photographic adapter as dew shield fully stretched） Focuser travel length 30mm Net weight 7.9kg Gross weight (Including tube ring & dovetail plate) 9.4kg Rear-end thread type M78×1-M54×0.75 M54×0.75-M54×0.75 M54×0.75-M48×0.75 (with M48×0.75 filter thread) Standard package items A 131F OTA, a pair of tube rings, a handle, a 300mm Losmandy dovetail plate, a set of photographic adapters