Brand: SharpStar

Askar FRA 500 Quintuplet APO Astrograph (FRA500)

FRA500

Brand: SharpStar

Askar FRA 500 Quintuplet APO Astrograph (FRA500)

FRA500

The FRA series are Askar's fast, wide astrographs. These are beautifully executed refractors that will deliver nice flat images with a huge field of view. The 90mm is a great size and will give great results.
  • 90mm Aperture
  • 500mm focal length
  • Quintuplet air-spaced APO Design
  • Full frame support
  • No need for flattener
  • 0.7x reducer (optional)
  • No need to calculate the backfocus
  • Retractable lens hood
  • 300mm dovetail plate
  • Multi-functional handle
  • 3.5" large rack pinion focuser
  • 1:10 fine adjustment
  • Various adapters
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$1,999.00 USD

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Why we love the Askar FRA 500 Quintuplet APO Astrograph (FRA500)

The FRA series are Askar's fast, wide astrographs. These are beautifully executed refractors that will deliver nice flat images with a huge field of view. The 90mm is a great size and will give great results.

The Askar FRA (Flatfield Refractive Astrograph) series are a modernized petzval design. They offer sharp and flat-to-the edge views with massive imaging circles. Askar uses two ED elements in the main objective to ensure images that are completely free of chromatic aberration.

What you get are expansive views with pinpoint sharp stars and color accurate images. These modern quintuplets leverage cutting edge camera technology to deliver stunning astrophotography results.

Product Description

Sharpstar Optics introduces Askar FRA500 astrograph, which is the youngest among the FRA family well-known to our customers. Compared with its siblings, the 500mm-focal-length refractor has an aperture size of 90mm (f/5.6), so Askar FRA500 can better fit into the scenarios of deep-sky imaging than the Askar FRA400. Besides, it is more lightweight and compact than Askar FRA600, which makes it a great choice for out-door observation or astrophotography.

Askar FRA500 has inherited the legacies of superior FRA- series designing. It boasts a quintuplet air-spaced APO optical structure, a “three plus two” Petzval lens combination. The front lens group consists of three lenses (including two pieces of ED glass) for excellent correction of aberrations. The posterior group is composed of two lenses separated by small space which is able to provide fine sharpness across the whole image. You may barely detect any blurry star at the edge of the image. FRA500 supports an image circle of amazing 55mm, much larger than the standard 44mm full-frame image circle. Its special back-focus design frees users from calculating confusing back-focus distance or rummaging around for a proper spacer. What you need to focus on is just to make your target stay in focus.

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.

The Askar FRA500 is 410mm long and weighs about 4kg, so it’s quite convenient for users to carry around or mount on an EQ mount. It’s particularly suitable for astronomy enthusiasts who frequently engage in long-distance trips or out-door astrophotography.

Askar FRA500 together with the FRA family is well received for large aperture, fast speed, delicate focusing system, unique optical design and the subsequently high-quality imaging results. Wish the Askar FRA500 be a loyal companion alongside your journey of astrophotography.

What can I see with a Askar FRA 500 Quintuplet APO Astrograph (FRA500)?

Here are some simulated views of common objects. Results with your telescope will vary with viewing conditions, obrits, equipment and more.

Jupiter with

25mm Eyepiece - 20x Magnification

(Sold Separately)

Jupiter with

10mm Eyepiece - 50x Magnification

Sold Separately

Jupiter with

5mm Eyepiece - 100x Magnification

Sold Separately

Moon with 25mm Eyepiece

20x Magnification

(Sold Separately)

Moon with 10mm Eyepiece

50x Magnification

Sold Separately

Moon with 5mm Eyepiece

100x Magnification

Sold Separately

Andromeda with 36mm Eyepiece

14x Magnification

Sold Separately

Andromeda with 25mm Eyepiece

20x Magnification

(Sold Separately)

Andromeda with 10mm Eyepiece

50x Magnification

Sold Separately

What's in the Box

  • FRA500 OTA
  • Pair of tube rings
  • Handle
  • Askar Losmandy dovetail plate
  • Conical extender
  • Manual

Specifications

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

Customer Reviews

Based on 1 review
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E
E.L.
In my opinion its a real marvel

I attached a full frame DSLR on this telescope and I don't have to crop anything!
The stars are round all across the FOV, even on the edges.

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