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Sky-Watcher Esprit 70EDX / Evostar 100EDX Flattener

Sky-Watcher Esprit 70EDX / Evostar 100EDX Flattener

by Sky-Watcher
SKU SW-S20216
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CA$310.00 - CA$310.00
CA$310.00
CA$310.00 - CA$310.00
CA$310.00
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  • 0.92x Reducer/Flattener
  • Compatible with the Esprit 70EDX and Evostar 100EDX
  • 44mm Image Circle for Full-Frame Sensors
  • Esprit 70EDX: 490mm f/7 to 450mm f/6.4
  • Evostar 100EDX: 700mm f/7 to 644mm f/6.4
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Sky-Watcher Esprit 70EDX / Evostar 100EDX Flattener

    The Sky-Watcher Esprit 70EDX / Evostar 100EDX Flattener is a 0.92x reducer/flattener that corrects the natural field curvature of both telescopes and delivers a flat field across a 44mm image circle. It also slightly shortens the focal length, bringing both scopes from f/7 to f/6.4 for faster imaging.

    44mm Flat Field for Full-Frame Sensors

    Without a flattener, stars at the edges of a large sensor turn into elongated shapes because a refractor's focal plane is curved. This flattener corrects that curvature across a 44mm image circle, wide enough to cover the diagonal of a full-frame sensor, so stars stay point-like from the center to the corners.

    0.92x Reduction: f/7 to f/6.4

    The 0.92x reduction speeds both telescopes from f/7 to f/6.4, which shortens the exposure time needed for the same signal by about 15% and slightly widens the field of view.

    • Esprit 70EDX: 490mm at f/7 becomes 450mm at f/6.4.
    • Evostar 100EDX: 700mm at f/7 becomes 644mm at f/6.4.

  • Which telescopes does this flattener fit?

    Sky-Watcher lists it for two telescopes: the Esprit 70EDX Super APO Triplet and the Evostar 100EDX APO Doublet. For the Esprit 100EDX, use the dedicated Esprit 100EDX Flattener (S20217).

    Will it cover a full-frame camera?

    Yes. The 44mm image circle is larger than the roughly 43mm diagonal of a full-frame sensor, and it covers APS-C and smaller sensors with room to spare.

    Does it reduce the focal length?

    Yes, slightly. It is a 0.92x reducer/flattener, so the Esprit 70EDX goes from 490mm to 450mm and the Evostar 100EDX from 700mm to 644mm, both at f/6.4.

    What back focus does the flattener need?

    Sky-Watcher had not published the back focus specification for this flattener at launch. Contact us before ordering and we will confirm the correct sensor spacing for your camera.

  • UPC 810098970754
    Optical Specifications
    Type Reducer/Field Flattener
    Reduction 0.92x
    Image Circle 44mm
    Compatibility
    Compatible Telescopes Esprit 70EDX, Evostar 100EDX
    Esprit 70EDX with Flattener 450mm at f/6.4
    Evostar 100EDX with Flattener 644mm at f/6.4

    • Esprit 70EDX / Evostar 100EDX Flattener

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  • Sky-Watcher 2-Year Limited Warranty