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Knife-Edge Focuser Product Description

Knife-Edge Focusing Procedure [PDF]

Knife-Edge Focuser Calibration Procedure [PDF]

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Astro Camera FAQ

Mitsuboshi Knife-edge Focuser
Interfacing Description

Each knife-edge focuser is supplied with an adapter to match your camera's lens interface. The examples on this page show the Nikon bayonet interface (35mm) and a Borg telescope with field flattener.

To focus, the camera body must be detached from the telescope and the knife-edge focuser attached temporarily.

since the knife-edge focuser and camera are both attached at the camera's lens interface, focusing is performed through the entire optical system, including any filters, and field flattener or focal reducer or barlow in use. If a camera teleconverter is being used, the camera should be detached behind it so focusing is done with the teleconverter installed.

If a dense filter is being used which interferes with the focusing, a clear filter of the same thickness should be substituted temporarily.

As shown below, exact focusing can only be acheived by precisely matching the focuser's position to the distance from the camera interface flange to the film plane. To do this, we recommend you send your camera body to Hutech at the time of your knife-edge focuser purchase. The focuser will be calibrated to your particular camera body with a precision micrometer.

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