TPO 1.25" Focal Reducer - 0.5X with 25mm Extension

  • Blackened Lens Edges
  • 2 Element Fully Multi-Coated Optics
  • Stackable Threaded Design
  • Nominal Reduction of 0.5X
  • Size: 1.25-inch
  • Includes a 25 mm Extension Tube!


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  • Regular price $24.26

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TPO 1.25" Focal Reducer - 0.5X with 25mm Extension

The Third Planet Optics 0.5x focal reducer screws on to any 1.25-inch eyepieces barrel and provides a nominal reduction of 0.5X. This package comes with a 25 mm extension tube for further reduction. The actual focal length reduction will vary a little depending on where the focal reducer is placed in the optical path. The reducer features a 2-element fully multi-coated optical design and blackened lens edges in a black anodized aluminum filter cell. It also has additional 1.25-inch filter threads, so you can screw/stack additional filters on to this reducer. Will work with all Meade DSI cameras, the Meade LPI, the Celestron NexImage, the Orion StarShoot cameras and most CCD cameras that use a 1.25-inch nosepiece!



OPT Product Number: OS-FR


Focal Length Reduction0.5X/ Nominal
Free ShippingYes
Optical CoatingsFully Multi Coated
Customer Reviews
4.0 Based on 5 Reviews
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Pete B.
United States United States
My Review

....It works complaints.... Quality and price is the reason I chose to order from OPT.

United States United States
TPO 1.25" Focal Reducer - 0.5X with 25mm Extension

Worked great with Mercury transition (11/11/'19).

Great bang for the buck !

I am about to order my second of these . I use it on a 12inch SCT with a Stellacam3, for the last 2 years. I have no edge issues or otherwise. I can say I am very pleased with the one I have, just would like another one in case something were to happen to this one .

Jason M.
Almost a wonderful product

My only issue with this product is the coma - it's pretty significant - generally I found myself cropping off the outter 20-30% of the image (752 X 582 cropped down to about 640x480 typically to trim off the worst of the coma. That being said, focal reducers typically exhibit better/worse coma depending on distance from the sensor. W/o a variety of different length nosepices for the DSI II, i could not experiment with varying the distance - it's possible there is a distance which eliminates this coma. I'd really like to see some tests because having a nosepiece focal reducer on the DSI II would be awesome.

Customer review

Bad coma when used with Meade DSI Pro II. I would not use it capture images. It may have some use for guiding though. It does widen the FOV in case a good guide star is out of the imager's normal FOV.