The 200-inch telescope is mounted in a equatorial alignment, with one axis of rotation, right ascension (or RA), parallel to the earth's rotation axis, and the other axis, declination, perpendicular to this. The telescope can be pointed at any object up in the sky by moving in both RA and declination. Then, as the earth turns, and the object appears to move across the sky from east to west, the telescope rotates slowly in RA in order to follow the object.

We have two animations showing a computer model of the telescope moving -- one with the central tube of the scope rocking back and forth in declination (Quicktime, 1.9 Mb), the other with the tube, horseshoe, and support arms twisting in right ascension (Quicktime, 2.5 Mb).