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Askar 111F 0.74× Reducer
Askar 111F 0.74× Reducer
Askar 111F 0.74× Reducer
Askar 111F 0.74× Reducer
Askar 111F 0.74× Reducer
Askar 111F 0.74× Reducer

Askar 111F 0.74× Reducer

by Askar
SKU ASK-ASAPO111F
$1,499.00 - $1,499.00
$1,499.00
$1,499.00 - $1,499.00
$1,499.00
Price Match Policy!
  • Reduces Telescope Focal Ratio to f/5.1
  • Creates a 566mm Focal Length Imaging System
  • Triplet Optical Design for Field Flattening
  • Provides Standard 55mm Back Focus
  • Weighs 0.5kg
1 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Askar 111F 0.74× Reducer

    The Askar 111F 0.74× Reducer converts the telescope into a fast f/5.1 astrograph, shortening the focal length to 566mm for wider fields of view. This triplet reducer establishes a standard 55mm back focus from its M48 male thread and weighs just 0.5kg, ensuring compatibility with a wide range of modern imaging cameras and accessories.

    f/5.1 Speed: A 0.74x Reduction for Wider Fields

    By reducing the focal ratio to f/5.1, this accessory significantly cuts down the required exposure time for faint deep-sky objects. The corresponding 566mm focal length widens the field of view, allowing you to frame large targets like the Andromeda Galaxy (M31) or the North America Nebula (NGC 7000) in their entirety on a full-frame sensor.

    Optical Correction: A 3-Element Design for Flat Fields

    The internal triplet lens design corrects for field curvature, ensuring stars remain sharp and round from the center to the edge of the frame. This level of correction is critical for modern, large-format CMOS and CCD sensors, eliminating optical distortions that would otherwise elongate stars in the corners of your images.

    Mechanical Design: 55mm Back Focus and Integrated Filter Threads

    Engineered for seamless integration, the reducer presents a standard 55mm back focus distance measured from the base of its M48 male camera connection. This simplifies the process of adding off-axis guiders or filter wheels into your imaging train. The reducer attaches to the telescope's focuser via an M68x1 thread, and the camera-side adapter includes threads for standard 2-inch (M48x0.75) filters.

  • What is the main benefit of the Askar 111F 0.74x Reducer?

    The primary benefit is speed. By converting the Askar 111F to an f/5.1 system with a 566mm focal length, it reduces exposure times by approximately 45% compared to the native focal ratio. This allows you to capture more data on faint objects in less time while also providing a wider field of view.

    How do I achieve the correct 55mm spacing for the 111F 0.74x Reducer?

    The 55mm back focus is measured from the base of the M48 male thread on the reducer to your camera's sensor. Most dedicated astronomy cameras and DSLR/mirrorless camera T-rings are designed to this 55mm standard, so in many cases, you can connect your camera directly. If you add a filter wheel or off-axis guider, you must use extension rings to ensure the total distance remains exactly 55mm.

    Can I use filters with the Askar 111F 0.74x Reducer?

    Yes. The reducer features a built-in M48x0.75 thread on the camera side, which allows you to directly attach standard 2-inch astronomical filters. This is ideal for using light pollution, narrowband, or LRGB filters without needing a separate filter drawer or wheel for simple setups.

    How will the 111F 0.74x Reducer change my image of the Andromeda Galaxy (M31) with the Askar 111F?

    The native focal length of the Askar 111F is too long to fit the entire Andromeda Galaxy (M31) and its satellite galaxies on a full-frame sensor. By shortening the focal length to 566mm, the 0.74x Reducer provides a field of view wide enough to capture the full expanse of the galaxy in a single frame, making it an essential accessory for imaging large celestial targets.

    Will the 111F 0.74x Reducer work with my full-frame camera on the Askar 111F?

    Yes, the triplet optical design is corrected for a large image circle sufficient for full-frame sensors. It effectively flattens the field to ensure that stars in the corners of a full-frame image remain sharp and are not affected by coma or field curvature.

    Is the Askar 111F 0.74x Reducer compatible with other telescopes?

    No, this reducer is an optically matched accessory designed specifically for the Askar 111F APO Triplet Refractor. Using it with other telescopes will likely result in poor optical correction and an inability to reach focus.

  • Reduced Focal Length 566mm
    Reduced Focal Ratio f/5.1
    Optical Design Triplet
    Back Focus 55mm (from base of M48 male thread)
    Telescope Connection Thread M68x1
    Weight 0.5 kg
  • Askar 1-Year Warranty