A Fifty-Metre Millimetre-Wave Single Dish: Surface Accuracy, Ruze Efficiency and Beam Size Computed Across the Submillimetre Bands

A 50 m single-dish telescope for millimetre and submillimetre astronomy is designed from the physics of its reflecting surface. With an actively controlled surface of 55 micrometres root-mean-square accuracy, the Ruze formula gives aperture efficiencies of 0.57 at 230 GHz, 0.40 at 345 GHz and 0.06 at 690 GHz, an effective area of 782 square metres and a gain of 0.28 K per Jy at 345 GHz. Beam widths are 6.6, 4.4 and 2.2 arcseconds at the three bands. The structure is estimated at 2,100 tonnes and the operating power at 620 kW. All figures are computed from the stated surface model; the design is simulated, not measured.