Askar - 90mm f/5.6 Quintuplet APO Astrograph

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The Askar FRA500 astrograph is the smallest telescope in the FRA family and is lightweight, compact and perfect as a superior grab and go scope. Its size is very conducive for astronomers on the go. Simple to set up due to the included adapters that can attach to any imaging device so you have less time spent setting up.

Askar 90mm f/5.6 Quintuplet APO Astrograph

The Askar FRA500 has benefited from the design of the FRA series. It offers a quintuplet air-spaced APO optical structure with a Petzval lens combination of a “three plus two” design. What this means is the front lens group consists of three of the lenses; tow of which are comprised of a two-piece ED glass which excels at correcting aberrations.

The rear set of lenses is made up of two lenses that are separated by a small space that offers an acute sharpness across the image you produce from edge to edge, offering an effective flat field. This will give you pinpoint, crisp stars to the edge of your field of view.

The FRA500 offers a superior 55mm imaging circle over the standard 44mm full frame imaging circle that other telescopes tend to offer. Combined with back focus design that frees the user from having to make complicated back focus calculations; what you need to attain focus with most imaging devices is with the Askar FRA500 astrograph so you can spend more time imaging and less time fumbling around with adapters.

Askar 90mm f/5.6 Features

  • Aperture size:90mm
  • Focal length:500mm
  • Focal ratio:f/5.6
  • Objective lens:Quintuplet air-spaced APO (including two ED glass)
  • Image circle:55mm
  • Back focus:158mm(from base of M48×0.75 thread on the conical extender to focal plane)
    • 85mm(from base of M86×1 thread on the rotator to focal plane)
  • Total length:452mm(410mm when the dew shield is contracted)
  • Net weight:4.1kg
  • Gross weight:5.2kg
  • Rear-end thread type:M86×1
  • Conical adapter:M48×0.75
  • Package items:an FRA500 OTA, a pair of tube rings, a handle, an Askar Losmandy dovetail plate, a conical extender, a manual

The Askar FRA500 is CNC machined with an attractive and decorative paint design making it pleasing to the eye and a practical layout of the components for ease of use. It features a retractable dew shield; when extended, the astrograph is only 452mm in length, when retracted; the FRA500 is only 410mm long.

At the rear of the FRA500 is the 3.5” focuser that features a dual-speed twin knobs; one for coarse adjustment and the other for1:10 fine adjustment which is handy for both visual observation as well as astrophotography.

The Askar FRA500 has a smooth coating with an even finish. The focuser also features a standard finder base; sporting a silver screw so you can mount guiders, finders and any other accessories you may wish to use.

 The Askar Quintuplet APO Astrograph also comes with tube rings with an attached carry handle on top which sports a M6 tapped hole to add accessories if needed and on the bottom, a 300mm Losmandy style dovetail plate.

What makes the Askar FRA500 a perfect grab and go scope is it’s length of 410mm and its weight of 4Kg’s so if you have a long way to travel, its easier to use this compact astrograph for your astronomy needs.

Warranty. manufacturer 1 year

More Information
Brand Askar
Free Shipping Free Shipping Available
Aperture 90mm
Backfocus Distance 158mm ( Varies depending on use)
Case Included No
Dovetail Or Saddle Length 30mm Losmandy style dovetail plate
Focal Length 500mm
Focal Ratio f/5.6
Focus Type Rack & Pinion dual speed
Diagonal Included Yes V Series
Optical Tube Material Aluminum
Optical Coatings Fully Multi-Coated
Optical Tube Length 452mm
Optical Tube Weight 4.1kg
In The Box
  • FRA500 Optical tube
  • Tube Rings
  • Handle
  • 300mm Losmandy dovetail plate
  • Conical extender
  • manual
  • FRA500 Optical tube
  • Tube Rings
  • Handle
  • 300mm Losmandy dovetail plate
  • Conical extender
  • manual
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