GSO's 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.
 
DESCRIPTION
Free aperture
22.5 mm
Optical system
multi-coated doublet
Reducing factor
0.5x (depending on the projection distance)
Function
0.5x Reducer for Visual and Astrophotography
Max. distance to the camera sensor
approx. 55 mm
Connection
1.25" filter thread (M 28.5 x 0.6) on both sides