William Optics Flattener 4 - 0.8X Reducer

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  • Regular price $309.00
  • William Optics Flattener 4 - 0.8X Reducer

    • Sale
    • Regular price $309.00
    • ITEM #

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    William Optics Flattener 4 - 0.8X Reducer

    The Flattener 4 - AFR-IV, 0.8X Reducer by William Optics:

    The revolutionary William Optics AFR-IV Adjustable Flattener and (0.75x-0.8x) reducer is made for 500 to 1000 mm refractors, including the William Optics FLT98, FLT110, FLT132, and others. This 2-element, 2-inch is black-anodized for durability and beauty. All internal surfaces are blackened to eliminate reflections.

    The WO AFR-IV Flattener has a rotating t-ring thread that will accept any standard t-ring for your camera. The included T-ring adapter comes with a locking screw and extra retaining screws. This field flattener inserts directly into a 2-inch focuser. It is easy to set the optimum back focus distance...just twist.


    William Optics AFR-IV Flattener Highlights:

    • The lens is designed to cover full size DSLR cameras with a clear lens aperture of 54 mm
    • The WO Flattener 4 has an excellent air-spaced doublet design with STM coatings, and is made with the best Ohara optical glass.
    • Superb William Optics anodized finish.
    • All internal surfaces are threaded and blackened.
    • Rotating T-ring thread for any 35 mm camera. The T-ring adapter is provided with a lock screw and extra lock retaining screws.
    • Will accept any standard T-ring for your camera.
    • Inserts directly into 2-inch focuser.
    • Lens-to-chip distance : 66-86 mm
    • 0.75x-0.8x Reducer
    • Rotating T-ring adapter
    • Clear Aperture : 54 mm
    • L 84 mm : W 95 mm : H 144 mm
    • Weight : 595 g


     OPT Product Number: WO-P-FLAT4


    Accessory TypeFlattener
    ManufacturerWilliam Optics
    Warranty2 Year Warranty

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    Questions & Answers

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    • Do you know if this will work on an Astro-Physics 130 GT with a focal length of 819mm? I am imaging with a Canon 60Da DSLR. Thanks, William

      There is a possibility that this will work, as it will work on a WO 132mm f/7 scope, but without testing it there would be now way to tell for sure how large the corrected field would be. The faster A-P scope will likely need additiona longer flattener-

    • I have a William Optics FLT 110, wich flattener is better for it? This one or the WO flattener 68II? Another question, the thread for the T-ring is m42 or m48 in the flattener 4? Thank you.

      Depending on which focuser you have on your FLT110, both could work quite well, but this is guaranteed to fit due to the 2" nosepiece on the scope side. The side facing the camera is a standard M42 T-ring, while the Flat68II uses an M48 Wide-T connection

    • I have a TS120 mm 900mm f7.5 telescope and a Televue TV-76 I use with an Atik infinity camera. My question is how does one calculate the adjustable focus distance the flattener 4 should be adjusted to? Is there a formula to use? I think the Atik Infinity

      The distance gets shorter the longer the scope's focal length gets. Here are recommended distances the manufacturer provides: FLT 98 - 76.8 mm (617mm FL) FLT 110 - 73.5 mm (770mm FL) FLT 132 - 71.5 mm (925mm FL) GT 102 - 76 mm (703mm FL) M90 - 77.3mm (6

    • Will this work with Orion EON 120mm (900mm focal length with 7.5 focal ratio) and QSI583 WSG CCD?

      This will probably work, although the 0.85x reducer that Orion and Sky-Watcher sell will likely offer better performance with a larger sensor. Back focus may be an issue, so use a short T2 spacer (5-7mm is ideal) to allow the camera to connect and see ho

    • Is there a 2" filter thread on a barrel side? Thanks

      Yes, the 2" barrel has an M48 filter thread for 2" filters.