The Askar FRA 600 f/5.6 is a professional apochromatic Petzval quintuplet refractor with an aperture of 108mm and a corrected field of 66mm in diameter.
The lenses are assembled in two groups: an air-spaced triplet on the front and a correcting doublet towards the rear. The objective lens includes two Extra Low Dispersion glass elements for a superb chromatic correction.
Differently from standard ED refractors, the Askar 600 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 an extra large 66mm fully corrected image circle and a focal ratio of f/5.6, this is the perfect astrograph for the advanced astrophotographer. The large rack and pinion 4.2" 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. The focuser is compatible with the ZWO EAF electronic focuser bracket.
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.


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