- GSO’s popular 1.25″ 0.5x focal reducer screws on to any accessory such as eyepieces, camera adapters, etc. that accepts standard 1.25″ threaded filters and provides a nominal reduction of 0.5x. Use of this focal reducer effectively halves the focal ratio of your telescope, resulting in a wider field of view and significantly shortened exposure times for astrophotography. For example, use of this reducer will convert an f/10 telescope into an f/5 scope.
- The 2-element reducer features fully multi-coated optics in a black-anodized aluminum filter cell. It also has additional 1.25″ female threads so you can screw/stack additional 1.25″ filters on to this reducer. This focal reducer will work well for visual use too when coupled with the right kind of eyepieces and telescopes; it is not recommended for very fast scopes or very wide angle eyepieces for visual applications.
- Note that the use of any optical element like barlows and focal reducers changes the focus point of your telescope, requiring additional in-focus or out-focus travel. The exact amount of focus travel required will depend on the optics and mechanics of your specific set-up (telescope, diagonal (if used), barlow/reducer, and eyepiece). Hence, be aware that you may not be able to reach focus with all eyepieces or in all configurations with a given barlow/reducer. In our tests, when screwed into an eyepiece, this focal reducer required approximately 8mm of additional in-focus travel so please make sure that your focuser can accommodate this travel requirement.
- Focal length (estimated) = 101 – 103mm (3.98 – 4.06″)
- Total item length (including external thread) = 13mm (0.51″)
- Total item length (excluding external thread) = 10mm (0.39″)
- Clear aperture = 22mm (0.87″)
- Weight = 15gms
- Made in Taiwan
1.25″ GSO 0.5X Focal Reducer – 1