The Askar 71F refractor from Sharpstar Optics is a quadruplet APO design offering 71mm aperture, 490mm focal length and a native focal ratio of f/6.9. With its quadruplet air spaced ED design, it removes chromatic aberrations offering sharp and pinpoint images for both astroimaging as well as observing.
The Askar 71F is a flat field refractor providing a 44mm image circle, large enough to support sensors up to full frame. It’s built-in flattening capabilities remove field curvature and eliminate the need for manual backfocus calculations and subsequent spacers. Included in the telescope package is an extension tube with M48x0.75 and M54x0.75 adapters to connect to a wide variety of cameras as well as a 2″ filter thread.
For astronomical observing, the package includes 8mm and 20mm eyepieces and a 1.25″ 45° prism, resulting in 60x and 25x magnifications respectively. The diagonal prism results in correct oriented photos and views.
The Askar 71F refractor is extremely lightweight weighing only 2.5 kg (3kg with mounting rings and dovetail). The telescope offers a retractable dew shield for portability and the inside of the scope is presented in a matte paint finish to eliminate light scatter. The Askar 71F handlebar includes a Synta-style finder base for accessories including guidescopes and WiFi camera controllers.
The included electronic ready focuser is a dual speed 2.4″ rack and pinion with 1:10 fine adjustment and a 360° field rotator at its rear. Also include is a Vixen style dovetail with 1/4 and 3/8 screw holes.
The Askar 71F refractor specifications include:
– Focal Ratio: f/6.9
– Optical Design: Refractor
– Telescope Aperture: 71mm (2.8″)
– Number of Elements: 4 (Quad)
– Focal Length: 490mm
– Image Circle: 44mm
– Focuser Style: 2.4″ Dual Speed Rack & Pinion
– Refractor Dew Shield Diameter: 3.45″ in.
– Telescope OTA Weight: 5.5 lb. OTA, 6.6 lb. Including Rings, Handle, and Dovetail Bar
– OTA Length Extended: 17in. With Visual Back; 18.6in. With Imaging Adapters
– OTA Length Retracted: 14.7in. With Visual Back; 16.3in. With Imaging Adapters
You can learn more about the Askar 71F refractor here.
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