<title>Spectroscopic survey telescope design: II. Tracking geometry</title>

Abstract

ABSTRACT Penn State University and the University of Texas are collaborating on an Arecibo-type opticaltelescope to be employed in a semi-transit mode for spectroscopic survey work. This telescope, clampedfirmly to its foundation during observation, will employ a 5-axis servo-mechanism in the telescope'supper section to track an object's image locus on the focal sphere. Once the telescope is clamped in anazimuth position, a time for each object relative to the telescope's structure may be determined,and therefore a strategy may be derived for driving the fiber-carrying optical head into conjunction with the image locus. The time is defined as the time when the image crosses the transit plane containing the primary mirror's center of curvature and normal to the central tangent of the image locus.The trigonometric mappingbetween the hour angle and declination functions of each object and the five coordinates x, y, 0, p, and PZ , (representing