World Leaders in Astronomical Equipments, Education & Services since 2001

GSO 0.5X Focal Reducer 1.25″

Original price was: ₹3,381.36.Current price is: ₹2,966.10. (Ex. GST)-12% OFF

Telescope Focal Reducer

  • 0.5x focal reducer effectively halves the focal length of a telescope, enabling lower magnification, a wider field of view, and shorter exposure times for astrophotography
  • Threads into eyepieces, camera adapters, and other accessories with standard 1.25″ threads
  • Fully multi-coated optics held in a black-anodized aluminum filter cell
  • Can be used with additional spacers (available separately) to achieve further focal reduction
  • Intended for use with with longer-focal-ratio telescopes and eyepieces of narrow to moderately-wide apparent fields of view

In stock


Focal Reducer Product Details

  • 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 Reducer Specifications

  • 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

Sales Package

1.25″ GSO 0.5X Focal Reducer – 1

World Leaders in Astronomical Equipments, Education & Services since 2001

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