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Askar 131F APO Flat-Field ED Quadruplet
Self-flattened quadruplet Astrograph which can be used for visual observing and astrophotography.
The Askar 131F is a large-aperture telescope designed for astronomy enthusiasts, featuring a 131mm aperture, 983mm focal length, and a native F7.5 focal ratio.
It employs a quadruplet optical lens design with three elements in the front and one in the rear, including one piece of ED glass to effectively suppress chromatic aberration.
The lens tube incorporates an internal baffle to block stray light, further enhancing image quality. The Askar 131F supports full-frame imaging and delivers excellent star performance across the frame.
Continuing the F series' self-flattening design, users can achieve optimal imaging without purchasing an additional flattener or calculating back focus. Simply connect the imaging accessory, achieve focus, and you're ready to shoot—streamlining the process and lowering the barrier to use.
The telescope comes standard with a photographic extension tube featuring a built-in 2-inch filter thread and offers M48×0.75 and M54×0.75 adapters for broad compatibility with DSLR cameras and dedicated astronomy cameras, meeting diverse imaging needs.
Staying true to the brand philosophy, the Askar 131F balances optical performance with user experience. The lens tube is crafted with high-quality CNC machining and painted finish, continuing the F series' iconic blue-and-white color scheme for strong visual identity.
Whether for deep-sky imaging or visual observation, the Askar 131F is an ideal choice for advancing your astrophotography journey.
Technical 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）
