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July 1st: Store will be closed for Canada Day. Orders placed that day will ship on July 2nd.
July 1st: Store will be closed for Canada Day. Orders placed that day will ship on July 2nd.

Sky-Watcher Evoguide 50ED Flattener

by Sky-Watcher
SKU SW-S20214
$115.00 - $115.00
$115.00
$115.00 - $115.00
$115.00
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  • Transforms the Evoguide 50ED/DX into a wide-field astrograph
  • Produces a 28mm corrected imaging circle for flat, sharp stars
  • Standard 17.5mm back focus simplifies camera and accessory spacing
  • Offers a massive 5.33° x 3.57° field of view with APS-C sensors
  • Connects securely via standard T-threads or a 1.25" nosepiece
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Sky-Watcher Evoguide 50ED Flattener

    The Sky-Watcher Evoguide 50ED Flattener unlocks the full astrophotography potential of the Evoguide 50ED and 50DX scopes, converting your high-end guidescope into a premium wide-field imaging instrument. This corrector produces a 28mm imaging circle, delivering pinpoint stars across the frame with cameras up to APS-C sensor size. With a generous 5.33° x 3.57° field of view on a crop-sensor camera and a standard 17.5mm back focus, it provides the optical correction needed to capture entire nebulae and star clusters in a single shot.

    28mm Imaging Circle: Edge-to-Edge Star Correction

    The primary function of this flattener is to eliminate the field curvature inherent in the Evoguide's fast optical system. It generates a 28mm corrected image circle, ensuring that stars in the corners of your frame are as sharp and round as those in the center. This level of correction is ideal for popular APS-C sized sensors, preventing elongated stars and allowing you to use the entire frame for your composition.

    17.5mm Back Focus for Simplified Imaging Trains

    Achieving correct spacing is critical for any flattener, and this unit makes it simple with a 17.5mm back focus requirement. This distance is easily managed with standard T-thread extension rings and adapters for most modern CMOS and DSLR astronomy cameras. The fixed spacing removes the guesswork, letting you connect your camera and start imaging with confidence that your optics are correctly aligned for the flattest possible field.

    • Direct T-Thread Connection: The flattener features a male T-thread for a secure, rigid connection to your filter wheel, off-axis guider, or camera's T-ring adapter.
    • 1.25" Accessory Mount: For smaller guide cameras or planetary imagers, a 1.25" opening provides a secondary connection method, adding flexibility to your setup.

    Capture Expansive Views: 5.33° x 3.57° on APS-C

    When paired with an APS-C camera, this flattener and the Evoguide 50ED create an imaging system with an immense 5.33° by 3.57° field of view. This is wide enough to frame the entirety of the Andromeda Galaxy (M31), the North American Nebula (NGC 7000), or the sprawling star-forming regions within the constellation Cygnus. It turns your guidescope into a dedicated, high-quality lens for capturing the largest deep-sky objects.

  • What is the main purpose of the Evoguide 50ED Flattener?

    The Evoguide 50ED Flattener corrects for field curvature in the Sky-Watcher Evoguide 50ED and 50DX telescopes. Without it, stars at the edge of an image will appear stretched or out of focus. This accessory ensures sharp, pinpoint stars across a 28mm imaging circle, making the guidescope suitable for high-quality, wide-field astrophotography.

    How do I achieve the required 17.5mm back focus for my camera?

    The 17.5mm back focus is the distance from the flattener's rear T-thread to your camera's sensor. Most dedicated astronomy cameras have a sensor-to-flange distance of around 12.5mm or 17.5mm. You may need a small T-thread spacer to achieve the exact distance. For DSLRs, the standard 44mm flange distance of a Canon EF-mount or 46.5mm of a Nikon F-mount means you will need a specific T-ring adapter designed for this back focus, which is typically shorter than the standard 55mm setup.

    Can I use a full-frame camera with the Evoguide 50ED Flattener?

    No, this flattener is optimized for a 28mm imaging circle, which is best suited for sensors up to APS-C size. While a full-frame camera (which has a ~43mm diagonal) will physically connect, you will experience significant vignetting and distorted stars in the outer portions of the frame beyond the corrected circle.

    What kind of field of view can I expect with the Evoguide 50ED Flattener on the Heart Nebula (IC 1805)?

    Using a camera with an APS-C sensor (like a ZWO ASI2600MC Pro or a Canon DSLR), the Evoguide 50ED with this flattener provides a field of view of 5.33° x 3.57°. This is an extremely wide field, perfect for capturing the entire Heart Nebula and its neighboring Soul Nebula (IC 1848) together in a single frame with room to spare.

    How do I connect a guide camera like a ZWO ASI120MM Mini to the flattener?

    The ZWO ASI120MM Mini has a 1.25" form factor. You can insert it directly into the 1.25" opening on the back of the flattener and secure it with the set screws. This allows you to use the Evoguide for both imaging and guiding simultaneously if you are using a separate, larger telescope as your main imaging scope.

    Are the dust caps on the Evoguide 50ED Flattener standard plastic caps?

    No, the flattener comes with high-quality, threaded metal dust caps. These provide superior protection for the optics by screwing on securely, preventing them from falling off and ensuring a better seal against dust compared to standard push-fit plastic caps.

  • Compatibility Sky-Watcher Evoguide 50ED, Sky-Watcher Evoguide 50DX
    Corrected Imaging Circle 28mm
    Back Focus 17.5mm
    Camera Connections T-thread (M42x0.75), 1.25" nosepiece receptacle
    Field of View (with APS-C Sensor) 5.33° x 3.57°
    Caps Threaded metal front and rear caps
    • Sky-Watcher Evoguide 50ED Flattener

      Evoguide 50ED Flattener

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    • Threaded Metal Dust Caps

      Threaded Metal Caps

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  • Sky-Watcher 2-Year Limited Warranty