TPO 0.75x Focal Reducer Kits for Ritchey-Chretien Telescopes

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  • Regular price $129.95

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Accessories Added

  • Reduction: Nominal 0.75x
  • Size: 2 Inch
  • Two Element Design
  • Two Year Warranty Included!


TPO 0.75x Focal Reducer Kits for Ritchey-Chretien Telescopes

Fully multi-coated optics, the Third Planet Optics 2" focal reducer will reduce your focal length by 0.75x shortening exposure times while still retaining a crisp image with excellent color and contrast. Extra long focal length to be perfectly compatible with the TPO RC telescopes, off-axis guiders, and filter wheels and is best for CCD sensors with up to a 15mm diagonal. Two element design effectively reduces focal ratios of the Third Planet Optics Ritchie Chretien from f/9 to f/6.75 and from f/8 to f/6.

OPT has also bundled this reducer with the necessary spacers and adapter to work with Canon DSLRs, Nikon DSLRs, and various CCD/CMOS cameras. The CCD/CMOS package comes with M48x0.75 spacer to have a remaining back focus of 55mm and the Canon and Nikon packages come with the same adapters as the CCD package but also include an M48 T-ring to directly attach to your DSLR.


Back Focus80mm
Camera Side ConnectionMale M48x0.75
Free ShippingYes
Scope Side Connection2" Nosepiece (housing)
Scope Side ConnectionFemale M48x0.75
Warranty2 Year Warranty


Redducer Only

  • TPO 2" 0.75x Focal Reducer for RC Telescopes

CCD/CMOS Package

  • PO 2" 0.75x Focal Reducer for RC Telescopes
  • TPO M48 20mm spacer
  • TOI M48 5mm spacer

Canon/Nikon Package

  • Everything in CCD Package
  • Canon or Nikon M48 T-Ring


Ask a Question
  • I have an Orion 8 f/8 Ritchey-Chretien Astrograph Telescope and currently using Atik filterwheel + atik 383L+ camera with a sensor size of 17.6mm x 13.52mm: Will it work properly ? How much will it increase the speed of my scope ? Thank you in advance

    Unfortunately, this reducer is only a reducer, not a reducer/flattener, and so it will only cover a 15mm diameter FOV (equivalent to a 12mm x 9mm CCD). Your camera has a sensor diagonal of 22.5mm, so the outer 30-35% will show distorted stars with this r

  • I have an 8 inch RC and a SBIG8300 that is 22.5mm diagonal measure. Also a CFW and OAG. Beyond 15 mm is the problem vignetting or are there significant aberrations too? How bad are the aberrations if any?

    The problem with this reducer is field curvature. The image will not be focused properly outside the 15mm image circle. For a larger CCD like yours, the AP CCDT67 may be a better choice, though with only a ~29mm image circle you may still have issues il

  • How would this work on my Meade ACF 16? And with a canon 6D DSLR?

    This reducer is not designed to work with the Meade ACF 16. There currently is no reducer available for the Meade 16" ACF

  • Will the Flattener/reducer work with the 10"RC and my SBIG STF8300C?

    This is not a reducer/flattener - just a reducer. It will be usable over the central 15mm diameter of your sensor, but an STF8300C has a 22.5mm diagonal and will not be corrected to the corners.

  • Compatible with TPO RC6 + DLRS Canon EOS 60D?

    The TPO 0.75x focal reducer is not a corrector and it will only cover a sensor 15mm across or smaller very well. A Canon 60D has a sensor 28mm across, so this will not work well with that camera.

  • What is the correct spacing for this focal reducer if I us a HuTech Flattener?

    You cannot use both the HoTech flattener and this reducer at the same time, because the proper spacing for the flattener is 55mm and the proper spacing for this reducer is ~80mm, which would put the reducer inside the flattener body.

  • What is the payload capacity??

    According to TeleVue, the legs have a stated capacity of 22 lbs, but this would be for use as a photo tripod (looking at the horizon). For any sort of telescope system where you would be pointed up in the sky and using high power, the usable capacity is m

  • Do these SC's have to have a wedge for photography?

    This is the optical tube only so it does not come with any mount. What you want to get if you want do to astrophotography is a German equatorial mount that can handle the weight of this OTA. Depending on your price range, there are several options availab

  • What is the correct spacing for this focal reducer? I just bought one and I have no idea how to configure my CCD camera and accessories.

    The ideal spacing is ~75mm from the CCD sensor to the thread on the focal reducer. This is not critical as this is just a reducer, not a flattener, so ~70-80mm should give acceptable results.