Celestron F/6.3 Focal Reducer Placement

    In reference to the correct placement of a F/6.3 focal reducer when added to one's imaging train, (my Canon 450D in the diagram) I comprised the above illustration.  A couple of references are cited below for a better understanding of the placement with other cameras or accessories.

http://en.wikipedia.org/wiki/Flange_focal_distance

    For the Celestron reducer with a focal length of 285mm working at f/6.3, the spacing is 105mm. For aftermarket uses the compression ranges from about 0.7 at 50mm spacing to about 0.5 at 225mm spacing.

http://www.celestron.com/

    For the Antares reducer/flattener, with a focal length of 220mm working at F/6.3, the spacing is 81mm.