The brand new ASKAR FRA series, short for “FLATFIELD REFRACTIVE ASTRAGRAPH,” revolutionizes refractive astrographs with built-in flat field correction. FRA, which is also suitable for visual observation, offers a versatile solution for generating high-quality flat frame images for astrophotography, making it one of the few great telescopes of versatile optical tube assemblies (OTAs).
The first member of the FRA family, featuring a Petzval-like quintuplet design (including two special ED glass elements), boasts a 72mm aperture, a 400mm focal length, and a focal ratio of f/5.6, providing a generous 44mm image circle for your imaging needs.
The FRA400 quintuplet astrograph showcases modern optical design with a retractable dew shield, a 3″ rack-and-gear-based high-precision reducer complete with a 360-degree rotator and M68×1 thread, as well as a 2″ adapter ring and a 1.25″ visual adapter. Furthermore, the reducer comes equipped with fine focal adjustment functionality, enabling precise calibration in practical observations or sky imaging using its optical tube assembly (OTA).
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