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Orion Telescopes
Orion Focal Reducer Corrector for ED100 Telescope
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  • Focal Reducer designed specifically for use with Orion's ED100 apochromatic refractor (ED100 sold separately)
  • Reduces the effective focal length of the ED100 refractor telescope from 900mm to 765mm - changes focal ratio from f/9.0 to f/7.65
  • Excellent for astrophotography use with DSLR cameras housing imaging chips as large as 36mm x 24mm
  • Two-element lens assembly, with one element made from ED glass
  • Fully multi-coated optics (all air-to-glass surfaces are multi-layer coated)

Learn more
Item #  05196

If you're an astrophotographer seeking even better performance from your Orion 100mm ED Refractor Telescope, our 0.85x Reducer-Corrector is for you. Designed specifically for use with this telescope and a DSLR camera, it reduces the scope's effective focal length to produce a faster system, which allows shorter exposure times. It also provides excellent field correction (flattening), yielding sharp stars out to the edge of a camera chip as large as 36mm x 24mm. That's even larger than the APS-C size chip found in DSLRs used most often by astrophotographers.

The Focal Reducer-Corrector achieves the nominal 55mm distance required from the optics to the DSLR's sensor for critical focus. It features a two-element lens assembly, with one lens made from high-quality extra-low dispersion (ED) glass. The optics are fully multi-coated to minimize light reflection off the lens surfaces. It reduces the focal length from 900mm to 765mm (f/9.0 to f/7.65), producing a faster system for improved astrophotograpy.

The Reducer-Corrector threads onto the focuser drawtube's male threads for a secure fit that will not introduce flexure. T-threads on the camera side accept your camera's T-ring. You will need a "wide" T-ring for your brand of camera, sold separately.

For owners of Orion's ED100 refractor who want to take astrophotos, this is a must-have accessory. It works well for daytime terrestrial photography too! Includes two thread-on lens caps.


Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-676-1343.


Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

Product Support
Visit our product support section for instruction manuals and more
  • Coatings
    Fully multi-coated
  • Number of elements
  • Clear aperture
  • Mounting
  • Mechanical profile
  • Weight (oz.)
  • Dimensions
    1.9 in. x 2.2 in.
  • Warranty
    One year
Orion Focal Reducer for ED100 Refractor Telescope

Orders received by 1pm Eastern Standard Time for in-stock item the same business day. Order received after noon will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.


This product is available to ship Standard delivery within the 50 US states, APO/DPO/FPO addresses and US territories/protectorates. Delivery is not available to Canada.

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