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Askar FRA500 90mm f/5.6 Quintuplet APO

by Askar
SKU ASK-FRA500
Original price $1,999.00 USD - Original price $1,999.00 USD
Original price
$1,999.00 USD
$1,999.00 USD - $1,999.00 USD
Current price $1,999.00 USD

Description

  • Compact and Portable
  • High-Quality Imaging
  • Precision Focusing
  • Elegant Design
Availability:
Backordered
Contact us to know when we will receive our next ones!

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More information

  • Description
  • Specifications
  • Sharpstar Optics is proud to introduce the Askar FRA500 astrograph, the latest addition to the well-known FRA family. With a 500mm focal length and a 90mm aperture (f/5.6), the Askar FRA500 is better suited for deep-sky imaging compared to the Askar FRA400. Additionally, its lighter and more compact design makes it an excellent choice for outdoor observation and astrophotography, especially when compared to the Askar FRA600.

    Introducing the Askar FRA500: Lightweight and Versatile for Deep-Sky Imaging


    The Askar FRA500 carries forward the superior design legacy of the FRA series. It features a quintuplet air-spaced APO optical structure with a “three plus two” Petzval lens combination. The front lens group consists of three lenses, including two ED glass elements, providing excellent aberration correction. The rear group has two lenses separated by a small space, ensuring sharpness across the entire image. This design virtually eliminates any blurry stars at the image edges. The FRA500 supports an impressive 55mm image circle, much larger than the standard 44mm full-frame image circle. Its special back-focus design eliminates the need to calculate confusing back-focus distances or search for the right spacer. All you need to do is focus on keeping your target sharp.


    Practical Elegance: The Askar FRA500's Design and Build


    Askar FRA500 is typically a wonderful mix of pragmatism and aesthetics. The astrograph shows smooth lines and a sound layout of components. From the front, the Askar FRA500 has an impressive dew shield decorated with a classic bright-red bezel ring. The total length of FRA500 is 452mm when the dew shield is stretched out and 410mm when contracted back. At the tail end of the astrograph locates a 3.5" massively-built focuser with dual-speed hand knobs (twin knobs for coarse adjustment and one 1:10 fine adjustment knob), which is of great use in real observation or astrophotography. The astrograph wears smooth coating and is evenly finished. The graduation inside of the focuser is quite clear and easily readable. The focuser is tough and solid, and on the left side of it, there is a standard finder base with a silver thumb screw. So the FRA500 can piggyback carry finders, guiders or other potential astronomy accessories. Askar FRA500 comes also with a pair of sought-after tube rings. On the top of the tube rings attached a handle and at the bottom, there is an Askar Losmandy-style dovetail plate. The combination of milk-white main tube and dew shield together with a high-gloss piano-black focuser makes the optical tube assembly calm and deep which is offset by the bright red decorative ring and tube rings.

    Compact and Portable: The Askar FRA500 for On-the-Go Astrophotography


    The Askar FRA500, measuring 410mm in length and weighing around 4kg, is convenient for users to carry and mount on an EQ mount. It's especially suitable for astronomy enthusiasts who often go on long-distance trips or engage in outdoor astrophotography. The Askar FRA500, along with the rest of the FRA family, is well-regarded for its large aperture, fast speed, delicate focusing system, unique optical design, and high-quality imaging results. We hope the Askar FRA500 becomes a loyal companion on your astrophotography journey.


  • Aperture 90mm
    Focal Length 500mm
    Focal Ratio f/5.6
    Objective Lens Quintuplet air-spaced APO (including two ED glass)
    Image Circle 55mm
    • 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)
    OTA Weight 4.1kg
    Total Weight (Including tube ring&dovetail plate) 5.2kg
    Rear-end thread type 86x1
    Conical Adapter 48x0.75
    Package items
    • 1 x FRA500 OTA
    • 1 x Pair of tube rings
    • 1 x Handle
    • 1 x Askar Losmandy dovetail plate
    • 1 x Conical extender
    • 1 x Manual