The Askar 0.74x focal reducer for the 131F APO is a dedicated reducer-corrector designed specifically for the Askar 131F Flat-Field telescope. It shortens the system focal length to 733.6 mm and changes the focal ratio to f/5.6, providing a wider field of view and shorter exposure times for deep-sky astrophotography. The reducer’s optical system maintains field correction and supports a 44 mm image circle suitable for full-frame sensors.

Key features

• dedicated 0.74x focal reducer for the Askar 131F Flat-Field telescope
• reduces the focal length of the Askar 131F to 733.6 mm
• changes the system focal ratio to f/5.6
• provides a wider field of view and shorter exposure times
• triplet optical design
• flat-field correction for astrophotography
• 44 mm image circle suitable for full-frame cameras
• 55 mm backfocus from the base of the M48 male thread
• M72 × 1 thread on both sides of the reducer
• M54 × 0.75 and M48 × 0.75 adapters for direct connection to the reducer
• rear adapter with M48 × 0.75 filter thread for 2" filters
• extension tube included
• direct connection to the 131F photographic extension tube
• precision CNC-machined housing
• front and rear metal threaded protective caps
• convex front lens - avoid touching it during installation

Kit contents

• Askar 0.74x focal reducer for 131F
• extension tube
• M54 × 0.75 adapter
• M48 × 0.75 adapter
• front metal threaded protective cap
• rear metal threaded protective cap

Technical parameters

• manufacturer: Askar
• model: 131F 0.74× Reducer
• accessory type: focal reducer / field corrector
• compatibility: Askar 131F Flat-Field
• reduction factor: 0.74x
• resulting focal length with Askar 131F: 733.6 mm
• resulting focal ratio with Askar 131F: f/5.6
• optical design: triplet
• image circle: 44 mm
• full-frame support: yes
• backfocus: 55 mm from the base of the M48 male thread
• front thread: M72 × 1
• rear thread: M72 × 1
• filter thread: M48 × 0.75 / 2"
• outside diameter: 76 mm
• mechanical length: 77 mm
• weight: 0.56 kg

The Askar 0.74x reducer for the 131F turns the Askar 131F into a faster astrograph with a wider field of view while preserving the field correction required for full-frame imaging.