Description
Askar FRA300 60mm f/5 Petzval Astrograph: Best Choice for Astrophotography
Since their inception, Askar FRA series short focal ratio astrograph has been very well received by astronomical amateurs. This year, we launched the FRA300 Pro —— the smallest 60mm F/5 Petzval astrograph with the fastest native focal ratio in the FRA series so far, its focal length is 300mm. The star is sharp and delicate. At the center of its field of view, the RMS radius can reach 2um. Even a serious user can also be satisfied when it comes to the shape of stars. It performs excellence with full-frame and supports 44mm imaging, which is a rare astrograph for amateur astronomers. Compared with F/6 or F/7,F/5 can effectively reduce the exposure time, helps you get the same exposure in less time. In addition, the entire OTA is compact, making it the portable choice for field photographers.
FRA300 Pro ‘s objective lens adopts a quintuplet fully air-spaced structure, including one piece of ED glass,it also adopts a fully-multi-coating to effectively remove stray light.
In particular, the rear group lens adopts the two pieces of far-separated refractive lenses, which improves both the star quality and the aberration correction performance , and has a very good control of full-frame peripheral light reduction.
Thanks to the native Petzval design, the user does not need to calculate the backfocus, as long as the focus is within a certain range is the optimal position.
Mechanically,FRA300 Pro is assembled with high-quality CNC-machined components , wrapped with smooth spray coating and light oxidation process,both beautiful and practical.The tube ring design is equally lightweight and stylish.Despite the increased cost, we want enthusiasts to use the FRA300 Pro that perform well in every way and are considered in every detail.
Aperture: | 60 mm |
Focal length: | 300 mm |
Focal ratio: | f/5 |
Telescope type: | 5-element (quintuplet) apo with 2-element ED lens |
Transport length: | 300 mm |
Weight: | 3.15 kg |
Camera side connection: | M76x1 M54x0.75 male thread, M48x0.75 male thread and T2 male thread |
Drawtube travel: | 20 mm |
Filter thread: | 2″ filter thread (M48x0.75) is integrated in the camera adapter (accessible after unscrewing the adapter) |
Working distance: | 45-65 mm from the T2/M48/M54 connection thread and 55-75 mm from the M76x1 external thread |
Dew shield diameter: | 92 mm |
Sample Images:
0.0 Average Rating Rated (0 Reviews)