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SharpStar 50EDPH 0.84x Focal Reducer

SharpStar 50EDPH 0.84x Focal Reducer

by SharpStar Optics
SKU SSO-SHREDU50
$109.00 - $109.00
$109.00
$109.00 - $109.00
$109.00
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  • Reduces telescope focal ratio to f/4.6
  • Converts focal length to 230mm
  • Quadruplet optical design with field flattening
  • Standard 55mm back focus requirement
  • Connects to cameras via M48x0.75 male thread
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  • Description
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  • SharpStar 50EDPH 0.84x Focal Reducer

    The SharpStar 50EDPH 0.84x Focal Reducer is an essential accessory engineered specifically for the 50EDPH refractor, transforming it into a faster, wider imaging instrument. This quadruplet reducer converts the telescope to a 230mm focal length at a fast f/4.6 focal ratio, all while maintaining a flat field. It establishes the standard 55mm back focus from its M48x0.75 threads and adds only 0.24kg to your imaging train.

    Faster, Wider Imaging at f/4.6 for the 50EDPH

    By shortening the telescope's effective focal length to 230mm, this 0.84x reducer significantly widens your field of view. The corresponding focal ratio of f/4.6 allows your camera sensor to gather light much more quickly, dramatically reducing exposure times required for faint deep-sky objects. This speed is critical for capturing expansive targets like the North American Nebula (NGC 7000) or large star clusters in a single frame.

    The quadruplet optical design doesn't just reduce the focal length; it also acts as a field flattener. This ensures that stars remain sharp and pinpoint across an APS-C sensor, correcting for the field curvature inherent in refractor optics and delivering a professional-grade image from edge to edge.

    Optimized for APS-C Sensors with 55mm Back Focus

    This reducer is engineered to fully illuminate APS-C sized sensors, making it a perfect match for a wide range of popular astronomy cameras and DSLRs. It features a standard M48x0.75 male thread for camera connection and requires a precise 55mm back focus distance from the base of this thread to your sensor for optimal performance.

    • Standardized Connection: The 55mm back focus is the industry standard for most cooled astronomy cameras when used with their included adapters, simplifying your imaging train setup.
    • Integrated Filter Threads: The reducer includes internal M48x0.75 threads, allowing you to directly mount standard 2-inch astronomy filters without needing a separate filter drawer.
    • Lightweight Design: At just 0.24kg, the reducer adds minimal weight and leverage to the focuser, helping to maintain system rigidity and prevent tilt.

  • What does the SharpStar 0.84x reducer do for my 50EDPH telescope?

    It converts your SharpStar 50EDPH into a faster and wider imaging system. It changes the focal length to 230mm and the focal ratio to f/4.6. This allows for shorter exposure times and fitting larger celestial objects into your frame, while the quadruplet design also flattens the field for sharp stars edge-to-edge on APS-C sensors.

    How do I connect my camera to the 50EDPH 0.84x Reducer to achieve the correct 55mm back focus?

    The reducer has a male M48x0.75 thread on the camera side. You must ensure the distance from the base of this thread to your camera's sensor is exactly 55mm. Most dedicated astronomy cameras and DSLR/mirrorless cameras with a standard M48 T-ring are designed to meet this 55mm spacing requirement with their included spacers.

    Can I use 2" filters with this SharpStar 0.84x reducer?

    Yes. The reducer has internal M48x0.75 threads, which is the standard threading for 2-inch astronomy filters. You can thread a filter directly into the reducer before attaching it to your camera.

    What is the new focal length and focal ratio of the SharpStar 50EDPH with this 0.84x reducer installed?

    With the 0.84x reducer attached, the SharpStar 50EDPH has an effective focal length of 230mm and a focal ratio of f/4.6.

    Is the SharpStar 50EDPH with the 0.84x reducer good for imaging the Andromeda Galaxy (M31) with an APS-C camera?

    Yes, it's an excellent combination for that target. The resulting 230mm focal length provides a wide field of view that can frame the entirety of the Andromeda Galaxy (M31) and its satellite galaxies on a typical APS-C sensor, while the fast f/4.6 focal ratio helps capture its faint dust lanes with shorter exposures.

    How does the f/4.6 focal ratio affect my exposures on faint targets like the Horsehead Nebula (Barnard 33)?

    The f/4.6 focal ratio is significantly "faster" than the native f/5.5 of the 50EDPH. For any given exposure time, you will collect roughly 44% more light. This means you can achieve the same signal-to-noise ratio in less time, which is a major advantage for capturing faint emission nebulae like the Horsehead Nebula (Barnard 33).

  • Focal Length (with 50EDPH) 230mm
    Focal Ratio (with 50EDPH) f/4.6
    Optical Design Quadruplet
    Required Back Focus 55mm (from M48 thread base)
    Camera Connection Thread M48×0.75
    Internal Filter Thread M48×0.75 (for 2" filters)
    Weight 0.24kg

    • SharpStar 50EDPH 0.84x Focal Reducer

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  • Askar 1-Year Warranty