An Optical Pointing Telescope for Radio Astronomy

Design details are given for a stable optical pointing telescope for radio astronomy. The telescope is a 100 mm f/15 refractor with the objective glued to a ring of three blade flexures, an insulated and vented Invar tube mounted on flexures, and an axially symmetric camera mount. For a pair of identical telescopes, the rms differential pointing stability is 0.1" hr^(-1) over 2 hr, 0.05" day^(-1) over 3 days, 0.03" K^(-1), and 0.1″ after a 90° change in elevation.