Instrument for Setting Radio Telescope Surfaces

摘要

The Green Bnak Telescope (GBT) (1) is a 100-meter radio telescope under construction by The National Radio Astronomy Observantory in Green Bank, WV. The GBT incorporates a first-of-its-kind active surface that will be adjusted under a closed-loop laser metrology system (2) to correct surface deflections. The goal is to maintain a reflector surfae accuracy of 0.220-mm rms in order to operate down to 3-mm wavelengths. (100 GHz). The reflector is made up of 2004 individual panels, each of which is manufactured to a section of a 60-meter focal length paraboloid surface to an accuracy of 0.075-mm rms. The panels rest on 2209 motor-driven actuators that adjust the surface to correct for deflections in the telescope backup structure. A bracket on each actuator joints the corners of four panels, so each actuator moves the four adjacent panel corers as a signle unit and thus the relative location of the four corners remains fixed.