The Carlsberg Meridian Telescope: the old micrometer

This is a description of the old micrometer system on the Carlsberg Meridian Telescope before the introduction of the new CCD system.

The Carlsberg Meridian Telescope measures the positions and magnitudes of stars, planets and their satellites and a selection of minor planets to a limiting magnitude of V=14.5. The measurements are made with a photoelectric scanning-slit micrometer as the objects cross the north-south meridian of the telescope. The positions and magnitudes of about 500 objects are measured each night. The zenithal accuracy for a single observation is 0.12 arcsec in right ascension and declination and 0.05 magnitudes in brightness. The telescope is being upgraded in the period 1995-97 by installing a CCD micrometer which will increase the absolute accuracy in position to 0.05 arcsec and extend the magnitude limit to V=16.