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The Camera Axis Mount

  The camera axis mount extends from under the Grating Module to provide for rotation of the camera about a vertical axis through the center of the front surface of the grating. This allows the camera-collimator angle to be varied between 11 and 45 degrees. The camera-grating distance can also be varied along the camera axis in order to place the camera mouth as close to the grating surface as possible without vignetting the light path from the collimator to the grating.

A camera-collimator angle of 12 degrees is typically used for the echelle grating (316@63.4) when used with the Simmons camera and 11 degrees when used with the Bench Spectrograph Camera. The low blaze angle gratings should normally use an angle of 30 degrees.

Sam Barden
Tue Aug 29 16:45:05 MST 1995