Meade's #777 Off-Axis Guider provides a means during long-exposure astrophotography for the photographer to monitor the tracking of the telescope, assuring that the telescope remains precisely positioned upon the object being photographed.
Like a T-Adapter, the #777 Off-Axis Guider couples the camera body to the telescope in a straight-through path. But unlike common t-mount adapters, it also diverts a small amount of the incoming light to be diverted at a right angle, allowing a star's position to be examined for tracking errors when compared with a known position upon an illuminated reticle eyepiece at the beginning of the exposure. Position corrections can then be effected using the telescope's hand controller or drive corrector.
Works with Many Telescopes with 2"-18 Threaded Rear Cells
The knurled slip ring attaches directly upon 2.00"-18 threaded rear cells of Celestron's 5.0-14.0" Schmidt-Cassegrains or Meade's 8.0-16.0" Schmidt-Cassegrains and 7.0" Maksutov-Cassegrain(Maksutov application requires extremely long exposures).
Select Guide Star of Your Choice
Slip ring allows 360° of guider body(telescope focuser can occasionally cause interference)
Causes Minor Vignetting with the Corners of 35mm-Type SLR Camera Imaging Area
Due to the design limitations, expect very minor vignetting of the extreme corners of film 35mm SLRs and full-frame digital SLRs(such as Canon 1Ds series); APS-C type digital SLRs will not exhibit such vignetting.