ASKAR FRA300 PRO F/5 APO REFRACTOR
Askar
Apochromatic Petzval quintuplet
3.12 kg
ASKAR FRA300 PRO F/5 APO REFRACTOR is backordered and will ship as soon as it is back in stock.
The Askar FRA 300 f/5 Pro is a professional apochromatic Petzval quintuplet with an aperture of 60mm and a corrected field of 44mm in diameter.
The lenses are assembled in two groups: an air-spaced triplet on the front and two far-separated corrective lenses in the rear. The objective lens includes one Extra Low Dispersion lens for superb chromatic correction.
Differently from standard ED refractors, the Askar 300 features a Petzval design that does not require to set the sensor to a specific distance to the last lens. That leaves the freedom to use any filter wheel, any off-axis guider or accessory without any worry to calculate the correct distance from the flattener.
With a large 44mm corrected image circle and a fast focal ratio of f/5, this is the perfect astrograph for the advanced astrophotographer. The large rack and pinion 2.5" focuser has a high payload capacity, it can be rotated 360° to perfectly frame the subject and it has a reduction gear of 10:1 for precise focusing.
All the lenses are fully multi-coated and the tube is internally blackened to reduce reflections and absorb stray light. The tube is made of aluminium, the rack and pinion focusing mechanism of brass and the mechanical components are engineered to provide the best rigidity, performance and durability.
Specifications
| Optical design |
Apochromatic Quintuplet air spaced with one ED element |
|
Objective diameter |
60 mm |
|
Focal length |
300 |
|
Focal ratio |
f/5 |
|
Image circle |
44 mm |
|
Mount attachment |
300 mm Vixen style bar |
|
Focuser |
Rack & pinion dual speed (10:1) 2.5" diameter |
|
Camera connection |
M54 x 0.75 male, M48 x 0.75 male, M42 x 0.75 male |
|
Backfocus |
71 mm from base of M54 & M42 threads, 67 mm from base of M48 thread |
|
Tube weight |
3.12 kg (including tube rings and dovetail bar) |
|
Tube length |
303 mm |
|
Tube diameter |
82 mm |
|
Dew shield diameter |
92 mm |
|
SKU |
AS-FRA300 |
Included Items
- Askar FRA300
- Tube rings
- 300mm Vixen style dovetail bar
- Handle on the rings
- M54 x 0.75, M48 x 0.75 & M42 x 0.75 imaging adapters
- Manual
Downloads
 ASKAR FRA300 manual (coming soon) |
Gallery
Customer Reviews
I have only had a chance to use it once to date. It is flat across the field in my 2600 MC Pro camera. Tiny bit of CA at the edges but its well controlled and only visible to the pixel peepers. It is well built-not quite William Optics levels but very good. It is sensitive to focus shift as the temperature drops so an EAF is recommended for long exposures, which I now have and is easily attached to the focuser. A good scope to consider against a Redcat 51 if you like a tradition focuser.
Extremely impressed, exactly what I was looking for in a wide field astrophotography telescope, as a step up from standard camera telephoto lenses. Image sharp across entire frame with no colour distortions. The telescope exceeded my expectations, which is rare when I purchase items, would recommend to anyone looking at this focal length.
Amazing little scope with a great flat field used in suburban Melbourne. Negligible CA and sharp edge to edge.
