Named in honor of Robert P. Thicksten, superintendent of the Palomar Observatory, California Institute of Technology since 1981. By his technical skill and his leadership of the Observatory staff, he has maintained and improved the Palomar telescopes (the 200-inch Hale Telescope, the 48-inch Oschin Schmidt, the 60-inch reflector and the 18-inch Schmidt) and their auxiliary instruments to keep them at the peak of their operational potential and, in doing so, provides invaluable support of the progress of astronomical research. (M 18139) _ _.