A. Pointing Procedure


The standard pointing procedure is to choose a bright star near the zenith, and send the telescope to the coordinates of the star. This will usually bring the star to within the field of view of the finder. Occasionally the pointing model will be very far off. In this case, users will need to bore-sight the telescope on a 1st magnitude star to reset the pointing model.

The finder has a set of luminous reticle lines to be used for fine pointing adjustment. When a pointing star is in the field of view of the finder, the telescope position should be adjusted by hand such that the star is positioned approximately as indicated in Figure 33.

  • Figure 33: Proper location of a positioning star in the finder fov with respect to the illuminated reticle lines.

    Once the star is placed correctly, return to the control room, and take a short exposure with the autoguider (1 or 2 seconds is usually sufficient). If you have the star placed properly, it should show up in the autoguider field. If you don't see anything, either the pointing is too far off, or the telescope is very far out of focus. If you see the star, adjust the pointing to place the star on the spectrograph slit. Once you have verified that it is on the slit, re-set the pointing model to the catalog position of the star. In most cases this will set the pointing correctly for the rest of the night. If you observe very far off-zenith, you may need to readjust the pointing slightly.


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    Updated: 2009 August 20 [pbe]