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The design, construction, and measurement of 10-m-class radio telescopes operating at millimeter and submillimeter wavelengths present many difficult challenges. The radio telescopes developed by Robert Leighton provide an economical solution to these problems. These 10.4-m-diameter telescopes have diffraction-limited beams at wavelengths as short as 300 mum. This paper describes the innovative techniques Robert Leighton developed to solve many of the problems encountered in building precision telescopes. The areas covered include the design of the homologous reflector support structure, the computer program used to accurately predict the deformations of the surface as a function of gravity, wind and temperature, the construction techniques used to minimize the stress and bending moments in the structure, and the methods developed for producing and measuring a 10.4-m-diameter reflector surface to the required accuracy.

The reflectors for the Leighton telescopes consist of honeycomb aluminum panels supported on a steel spaceframe backing structure. The spaceframe utilizes precision machined members and pin joints. The 84 panels form a hexagonal tiling pattern in the aperture plane and are figured using a custom-built machine that cuts the parabolic shape into the exposed honeycomb core while all of the panels are assembled on the backing structure. The aluminum reflecting surface is then applied to the front of each panel.

The techniques used to fabricate the Leighton telescopes have proven to be very successful. The telescopes are routinely fabricated and installed with an rms surface accuracy of less than 35 mum without any adjustments or corrections. The computer calculations of the homologous deformation of the telescopes as they move in elevation have been verified by holographic measurements of the aperture field pattern using astronomical sources. The telescopes have survived 15 years of operation in the 1200-m altitude desert site at the Owens Valley Radio Observatory with no evidence of degradation. A Leighton telescope installed at the Caltech Submillimeter Observatory on Mauna Kea, HI, has achieved an accuracy of < 20 mum.