1 x Astroscope. So the FRA series is among the few versatile and quality astrophotographic devices in the current astronomy market. - The FRA400 quintuplet astrograph has adopted modern optical design with a retractable dew shield, a 3" rack-and-gear-based high-precision reducer containing a 360-degree rotator, M68×1 thread, a 2" adapter ring and a 1.25" visual adapter.
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Specially designed for the FRA400C, this 0.7x reducer adopts a triplet lens design, it can reduce the overall focal length to 280mm and the focal ratio to F3.9 while providing a flat-field correction.
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The reducer has a backfocus of 55mm and includes threads for M48X0.75 (2") filters. We have a large inventory.
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The FRA400C mirror is rotatable, making it easy to adjust the angle when shooting. The FRA400C is an astrograph with an aperture of 72mm, a focal length of 400mm and a native focal ratio of 5,6. The FRA400C has an aperture range of F22 to a maximum of F5.6.
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1 x Astroscope. So the FRA series is among the few versatile and quality astrophotographic devices in the current astronomy market. - The FRA400 quintuplet astrograph has adopted modern optical design with a retractable dew shield, a 3" rack-and-gear-based high-precision reducer containing a 360-degree rotator, M68×1 thread, a 2" adapter ring and a 1.25" visual adapter.
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The reducer has a backfocus of 55mm and includes threads for M48X0.75 (2") filters.
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The back focus of FRA400 is 140mm, starting from the base of mounting thread on the housing to the focal plane. And users don't need to worry about the calculation of back focus when using FRA400, as long as the object in the objective lens is focused.
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