Abstract

We have performed an experiment to characterize the performance of a device designed to accurately maintain the relative alignment of large-aperture optical telescopes separated by large distances. Two-body relative attitude control system (TRACS) measures and controls relative angular motions between two V-shaped Zerozur mirrors separated by 2 m. The design eliminates first-order errors due to laser instability and small amplitude motions in the optical components. This makes it possible to measure all three relative tilts to within 0.2 µrad. This is accomplished by directly comparing the beam that samples the orientation of the Zerodur mirrors to a reference beam that carries common path errors. The experiment, which was performed in a vacuum, measured the resolution of TRACS by means of two identical systems that took independent sets of data simultaneously from the same pair of platforms. By applying thermal loading to the most sensitive components, the thermal stability of TRACS was also determined.

© 1990 Optical Society of America