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Askar 203APO f/7 Triplet APO Refractor

by Askar
SKU ASK-203APO
Original price $8,579.00 USD - Original price $8,579.00 USD
Original price
$8,579.00 USD
$8,579.00 USD - $8,579.00 USD
Current price $8,579.00 USD
Price Match Policy!
  • 203mm Aperture Triplet Air-Spaced APO Objective
  • 1421mm Focal Length at f/7
  • Includes one ED (Extra-Low Dispersion) Glass Element
  • Retractable Tube Design for a 1145mm Minimum Length
  • 23.5kg Gross Weight with Included Rings and Plate
  • 3.5-inch Dual-Speed Rack & Pinion Focuser with 100mm Travel
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Framing Simulator
Framing SimulatorInstant FOV Preview

Preview your camera's FOV

See exactly how your targets fit with the Askar 203APO f/7 Triplet APO Refractor, on real sky survey data.

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Visual Simulator
Visual SimulatorInstant FOV Preview

Preview your eyepiece's FOV

See exactly what the Askar 203APO f/7 Triplet APO Refractor shows you, on real sky survey data.

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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty
  • Askar 203APO f/7 Triplet APO Refractor

    The Askar 203APO f/7 Triplet APO Refractor combines a 203mm aperture with a 1421mm focal length for visual and imaging use; its limiting magnitude is 13.3. Its triplet air-spaced objective, featuring one ED glass element, is housed in an optical tube with a gross weight of 23.5kg and a transport length of just 1145mm thanks to its retractable design. The 3.5-inch dual-speed rack-and-pinion focuser offers 100mm of travel, it supports a 44mm image circle, and a 500mm Losmandy-style dovetail plate is included.

    203mm f/7 Triplet APO: ED Glass for Apochromatic Correction

    The core of the 203APO is its 203mm triplet air-spaced apochromatic objective. By incorporating a specialized ED (Extra-low Dispersion) glass element, the optical system corrects chromatic aberration; Askar's APO series uses special optical designs and multiple lens elements to correct chromatic aberration for higher-quality detail and color accuracy.

    This level of color correction is critical for an instrument with this much light-gathering power. The large aperture allows you to push magnification for visual work and shorten exposure times for imaging, revealing fainter structures and resolving closer double stars than a smaller instrument can.

    A 1145mm Transport Length: Retractable Tube for Portability & Binoviewers

    Despite its large 203mm objective, the Askar 203APO is engineered for field use. A retractable dew shield brings the shortest overall length to 1145mm (1335mm with the dew shield stretched), and the OTA ships in an aluminum box. The rear lens tube is also retractable (150mm), with a rudder-type locking ring; it is strengthened so the optical axis is not affected when the tube is stretched.

    • Binoviewer Mode: With the rear lens tube contracted, the 203APO can be used with a binoviewer for visual observation.
    • Diagonal Mode: With the rear lens tube stretched, the 203APO can be connected to a diagonal and an eyepiece.

    3.5-inch Rack & Pinion Focuser: 100mm of Travel and 360° Rotation

    The 203APO is equipped with a large 3.5-inch dual-speed rack and pinion focuser which is compatible with most motorized focusers on the market. The focuser provides a generous 100mm of travel, with laser-engraved scales in the length and circumference directions for adjusting and recording. A big 360° rotator lets you frame your target without rotating the optical tube.

    The focuser is CNC machined, has an anti-reflective internal design with matting paint against stray light, and an enlarged rotator locking screw that prevents image shifting during shooting. Two finder bases sit on both sides of the focuser, and 2-inch and 1.25-inch visual adapters are fitted at the rear.

    Imaging with a 44mm Image Circle

    The 203APO supports a 44mm image circle. As with any triplet refractor, a flat field across a large sensor needs a dedicated corrector.

    Askar has announced a dedicated 203APO reducer and flattener; neither is part of this package, and no figures for them are given.

    23.5kg Mounting System: Triplet Rings and a 500mm Losmandy Plate

    Supporting the 18.5kg optical tube is a robust set of hardware that brings the total gross weight to 23.5kg. The tube rings have an enhanced triplet design with thumb screws for easy opening and locking, and their base is heightened for more space. They attach to the 500mm Losmandy-style dovetail plate, which is compatible with most equatorial mounts and bases and has multiple holes for position adjustment.

    An extended 402mm handle with a special slot design is mounted on top of the rings, which not only makes transport and setup easier but also serves as an additional mounting point for a guide scope or other accessories. The extended length of the 500mm dovetail plate provides ample room to slide the entire assembly forward or backward, making it easier to balance when using different visual or imaging setups.

    Askar 203APO vs. 185APO: A 20% Gain in Light-Gathering Area

    The 203APO has a 20% larger effective aperture area than the 185APO.

    • Askar 203APO Advantage: The larger 203mm aperture gathers approximately 20% more light. This results in brighter images, shorter exposure times for faint deep-sky objects, and a higher theoretical resolution for splitting close double stars and resolving fine planetary detail.
  • How does the Askar 203APO's retractable rear tube help with binoviewers?

    Binoviewers need extra inward focus travel. With the rear lens tube contracted, the 203APO can be used with a binoviewer for visual observation.

    Is the Askar 203APO suitable for imaging Jupiter or Saturn?

    The large 203mm aperture gives high resolving power, and the f/7 focal ratio is an excellent starting point for high-resolution planetary imaging. When combined with a high-quality 2.5x or 3x Barlow lens and a high-frame-rate planetary camera, the Askar 203APO can achieve the long effective focal lengths needed to capture fine details like the Cassini Division in Saturn's rings, cloud bands on Jupiter, and surface features on Mars.

    Does the Askar 203APO require a field flattener for imaging?

    Yes, for a flat field on large sensors (APS-C and full-frame) a dedicated corrector is needed. Askar has announced a 203APO reducer and flattener; none is included.

    Can I use standard 2-inch and 1.25-inch accessories with the Askar 203APO?

    Yes. The Askar 203APO is equipped with a large 3.5-inch focuser that terminates in a standard 2-inch opening. It also includes a 2-inch to 1.25-inch adapter, for 2-inch and 1.25-inch diagonals and eyepieces.

    What is the purpose of the long 500mm Losmandy dovetail plate on the 203APO?

    A long and heavy telescope like the Askar 203APO requires careful balancing on an equatorial mount, especially when adding cameras, filter wheels, and guide scopes. The included 500mm Losmandy plate provides a wide range of adjustment, making it much easier to slide the entire 23.5kg assembly forward or backward to balance it in both Right Ascension and Declination.

    How portable is the Askar 203APO with its 1145mm length?

    While the 203APO is a large instrument, its retractable dew shield reduces the transport length to 1145mm. It comes with a fitted aluminum case with wheels for easier transport. The main consideration for portability is its 23.5kg gross weight, which requires a heavy-duty mount and a deliberate setup and teardown process at a dark-sky site.

    What are the two finder bases on the Askar 203APO's focuser for?

    The dual finder bases provide flexibility. You can mount a finder scope on either side of the focuser depending on your preference. The second base can also be used to mount an additional accessory, such as a small guide scope, without interfering with your primary finder.

    How does the 360° rotator on the Askar 203APO's focuser work?

    The 360° rotator is a ring at the rear of the focuser that allows you to turn your entire imaging train (camera, filter wheel, etc.) without loosening the focuser or rotating the main tube. You simply loosen the rotator's locking screw, turn your camera to the desired framing angle, and then tighten the screw to lock it in place. This is essential for precise composition of astrophotos.

    Does the Askar 203APO come with a case for transport?

    Yes. The Askar 203APO includes a rigid aluminum case with custom-cut PE foam interior. The case is designed with wheels for easier transportation and has extra space reserved for accessories like an electronic focuser.

  • Aperture Size 203mm
    Focal Length 1421mm
    Focal Ratio f/7
    Objective Lens Triplet air-spaced APO (including one ED glass)
    Total Length 1145mm (dew shield contracted) / 1335mm (dew shield stretched)
    OTA Weight 18.5kg
    Gross Weight 23.5kg (including tube rings and dovetail plate)
    Adapters 2" and 1.25" visual adapters
    Image circle 44mm
    Focuser type 3.5in dual-speed rack and pinion with 360° rotator
    Focuser travel 100 mm
    Dovetail included 500mm Losmandy-style
    Mount No
    • 203APO OTA

      × 1

    • Tube Rings

      × 1 group

    • Handle

      × 1

    • Askar 500mm Losmandy Dovetail Plate

      × 1

    • Aluminum Box

      × 1

  • Askar 1-Year Warranty