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

摘要

With a diameter of 15m the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the worlddesigned specifically to operate in the submillimeter wavelength region of the spectrum. It is situated close to the summitof Mauna Kea, Hawaii, at an altitude of 4092m. Its primary reflector currently consists of a steel geodesic supportingstructure and pressed aluminium panels on a passive mount. The major issues of the present reflector are its thermalstability and its panels deterioration.A preliminary design study for the replacement of the JCMT antenna dish is here presented. The requested shape errorfor the new reflector is &20μm RMS.The proposed solution is based on a semi-monocoque backing structure made of CFRP and on high precisionelectroformed panels. The choice of CFRP for the backing structure allows indeed to improve the antenna performancein terms of both stiffness and thermal stability, so that the required surface accuracy of the primary can be achieved evenby adopting a passive panels system. Moreover thanks to CFRP, a considerable weight reduction of the elevationstructure can be attained.The performance of the proposed solution for the JCMT antenna has been investigated through FE analyses and theassessed deformation of the structure under different loading cases has been taken into account for subsequent errorbudgeting.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.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.