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Astro-Physics 0.72x Quad Telecompressor Corrector


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  • The Quad Telecompressor Corrector was previously sold as a bundle with the back focus spacer extension, but are now being sold separately. See chart.

Product Details

  • The Quad Telecompressor Corrector will reduce your f/value and expand your field, speeding up the collection of photons! Even better, it will do all of this with pin-point stars to the corners of even your full frame 35 mm camera sensor. It is designed with four carefully matched glass elements that are coated with the latest, most sophisticated multi-coatings to produce high-quality optics. All mechanical parts, including the covers, are CNC machined and black anodized for a sleek finish. The male threads are 3.27" x 16.

    You will want to determine the appropriate back focus spacer for the telescope that you plan to use and purchase it separately. If you own more than one of the telescopes listed below, then you are in luck! You can just purchase the appropriate back focus spacer to use the QUADTCC with that scope as well.

    For the TEC focusers, you will also need to order a Drawtube Endcap (S35RFAA). It screws right onto the drawtube's 4.1" x 24 thread (same as Starlight Instrument's 3.5" focuser endcap thread). While the QUADTCC was specifically designed for the 3.5" focuser, it can easily be used with Astro-Physics 4" focuser fitted with the 4" to 3.5" adapter with thumbscrews for 4" focuser (ADA435).

    The following chart shows the back focus spacing (as measure from the rear flange of the back focus spacer) is 80.8 mm +/- 1.0 mm.

     Telescope Focuser or Adapter Required Back Focus Spacer Required Back Focus Spacing Spacing w/ 3.27" Extension Spacing w/o Extension
    AP 130 GTX None EXT327-22.1 22.1 mm 80.8 mm 102.9 mm
    TEC 140 S35RFAA EXT327-18.3 18.3 mm 80.8 mm 99.1 mm
    TEC 160 S35RFAA EXT327-17.0 17.0 mm 80.8 mm 97.8 mm
    TEC 180 S35RFAA EXT327-16.0 16.0 mm 80.8 mm 96.8 mm
    ???? S35RFAA EXT327-34.1 (new in May 2021) 34.1 mm 80.8 mm 114.9 mm


    In most imaging setups, it's not necessary to modify the spacing distance. However, there may be some camera / sensor combinations that can benefit by making slight changes to the spacing. A set of three 1 mm thick spacer rings can be used in these special circumstances to modify the back focus spacing of the Telecompressor Corrector. There are both 3.27" Spacer Rings (SRSET-327) and 2.7" Spacer Rings (SRSET-27).

  • included items

    • The Quad Telecompressor Corrector was previously sold as a bundle with the back focus spacer extension, but are now being sold separately. See chart.

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Netherlands Netherlands

Superb reducer

Superb optical performance and superb heavy-duty build quality AND fits completely into Feathertouch 3.5" focuser with special adapter.