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Adjusting the CCD Camera for Optimal Collimator Focus

The collimator may be adjusted to bring the spectrograph into focus. If the collimator has to be set far from its optimum position astigmatism will result. The optimum collimator position for the wide collimator is at about 10000 microns. If best focus is obtained outside of the range microns then the CCD dewar should be repositioned either further or closer to the camera mount. This is achieved by turning capstans A, B and C by the same amount. As a guide:

For example, if you achieve a focus with the collimator at 20000 microns, changing the capstan settings of A, B and C by ??mm will bring the spectrograph into focus at a collimator position of 10000 microns.

(N.B. Care here in altering the capstans should mean that no further tilt is introduced into the system!)

Mon Mar 14 16:50:31 GMT 1994