Sirius Focal Reducer F/6.3 for SCT

Improves edge-of-field focus, reduces exposure times and widens the field of view. Threads into rear cell of any SCT with a standard SCT Thread. Can also be used to increase field of view and reduce magnification for visual applications.

Varying the Reduction Factor of a Focal Reducer

The actual reduction will vary a little over or under 0.63x depending on exactly where the focal reducer is placed in the optical path. The focal length specification of this reducer is 240mm. Hence, the required spacing of this specific reducer is 88mm, i.e., this reducer will provide a reduction of 0.63x when the SCT side of it's lens assembly is placed 88mm from the imaging CCD or focal point of an eyepiece. Move the focal reducer closer to the eyepiece/camera and its reduction factor will decrease. Move it away and the reduction provided will increase.

By using additional spacers or extension tubes (not included), you can vary the amount of reduction you obtain with this reducer.

However the "sweet spot" for this reducer is 88mm spacing, this willl give the proper field flattening effect.

Compatable Telescopes

• Any Meade or Celestron SCT
• Skywatcher 127, 150 and 180 Maksutov Cassegrain (2" focuser models)
• Saxon 127, 150 and 180 Maksutov Cassegrain (2" focuser models)