New technologies and new performances of the JCMT radio-telescope: a preliminary design study

S. Mian; S. De Lorenzi; L. Ghedin; F. Rampini; G. Marchiori; S. Craig

doi:10.1117/12.927124

13 September 2012 New technologies and new performances of the JCMT radio-telescope: a preliminary design study

S. Mian, S. De Lorenzi, L. Ghedin, F. Rampini, G. Marchiori, S. Craig

Proceedings Volume 8450, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II; 84505O (2012) https://doi.org/10.1117/12.927124
Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands

Abstract

With a diameter of 15m the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the submillimeter wavelength region of the spectrum. It is situated close to the summit of Mauna Kea, Hawaii, at an altitude of 4092m. Its primary reflector currently consists of a steel geodesic supporting structure and pressed aluminium panels on a passive mount. The major issues of the present reflector are its thermal stability and its panels deterioration. A preliminary design study for the replacement of the JCMT antenna dish is here presented. The requested shape error for the new reflector is <20μm RMS. The proposed solution is based on a semi-monocoque backing structure made of CFRP and on high precision electroformed panels. The choice of CFRP for the backing structure allows indeed to improve the antenna performance in terms of both stiffness and thermal stability, so that the required surface accuracy of the primary can be achieved even by adopting a passive panels system. Moreover thanks to CFRP, a considerable weight reduction of the elevation structure can be attained. The performance of the proposed solution for the JCMT antenna has been investigated through FE analyses and the assessed deformation of the structure under different loading cases has been taken into account for subsequent error budgeting. Results show that the proposed solution is in line with the requested performance. With this new backing structure, the JCMT would have the largest CFRP reflector ever built.

Citation Download Citation

S. Mian, S. De Lorenzi, L. Ghedin, F. Rampini, G. Marchiori, and S. Craig "New technologies and new performances of the JCMT radio-telescope: a preliminary design study", Proc. SPIE 8450, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II, 84505O (13 September 2012); https://doi.org/10.1117/12.927124

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KEYWORDS

Reflectors

Antennas

Telescopes

Space telescopes

Aluminum

Astronomical telescopes

Optical instrument design

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