Since their
inception, Askar FRA series short focal ratio astrograph have been very well
received by astronomical amateurs. This year, we launched the Askar 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.
The Askar 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.
The focuser is
2.5"rack-and-pinion focuser, which is solid and beautiful. It's designed
with dual-speed hand knobs, twin knobs for coarse adjustment and a fine
adjustment knob to accurate the focus, equipped with a universal M48X0.75
thread adapter. There are also two separate M54X0.75 and M48X0.75 adapters in
the standard kit for easy access to a variety of imaging equipment and
accessories. The end is equipped with a 360° rotator, which is convenient for
users to rotate at any angle when shooting.
FRA300 Pro also
comes standard with a multi-function handle and a 300mm vixen-style dovetail
plate, which can be directly connected to various mounts and accessories, the
multi-functional handle can also be connected to the universal vixen-style
finder base. The 300mm dovetail plate allows the astrograph to maintain balance
on the mount.
