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Large Format OAG

Slim-profile OAG

Off-Axis Guiders

The Mitsuboshi off-axis guiders are designed to be used in conjunction with a variety of popular digital cameras and telescopes.

Use of an off-axis guider (OAG) eliminates the possibility of differential flexure (e.g. between guidescope and imaging scope) as well as makes for a more compact arrangement, an advantage for photo "expeditions."

These lightweight, 36mm thick units (see also new OAG7 Slim-profile units) are specifically designed to handle full-frame, 35 mm sized cameras (OAG5 model shown here) and large format digital imagers such as the Kodak KAF-16803 (OAG6 model). Rotatable interfaces on both sides of the OAG allow for guide star selection without changing the camera's orientation. Shown below is the M57-AD taper adapter.


The radial position of the pick-off mirror is easily adjusted for optical system parameters such as the internal diameter of the telescope/camera interface, effective image circle of the optics, and imaging sensor size. The distance of the pickoff mirror into the telescope's light cone may be adjusted between 17 and 34mm for the OAG5, and between 16 and 33mm for the OAG. Refer to the diagram below to see the mirror position adjustments.

The size of pickoff mirror is 12mm square with a guide port diameter of 11mm, making the effective autoguider opening 11mm.


Available Accessories:
  • Telescope Interfaces
    • Borg M57
    • Standard SCT thread
  • Camera Interfaces
    • SLR cameras
    • T-threaded CCD cameras
    • SBIG STL cameras
  • Guider port
    • Extension tubes available in several lengths

Besides providing for rotation with respect to the camera position, the OAG pickoff may be shifted to provide a radial degree of freedom in selecting the guide star.

At left, the OAG is shown with an optional Borg 7315 helical focuser / 1-1/4" eyepiece holder. This makes the guider optical path 13mm longer than the standard configurations shown above.
Sample Configurations:
  • SBIG STL11000
       MTAC - OAG5 - 7352 - 7000 - M49.8-STL - STL11000
       MTAC - OAG6 - M57R* - 7352 - 7000 - M49.8-STL - STL11000
  • Canon 5D
       MTAC - OAG5 - 7352 - 7000 - 5005 - Canon 5D
       MTAC - OAG6 - M57R* - 7352 - 7000 - 5005 - Canon 5D
  • Apogee U16 and U9000
       MTAC - OAG6 - M84R* - MCAC - Apogee
* supplied with OAG6