VISTA - the world's largest telescope dedicated to ground-based survey work should be completed by early 2008. Capable of supporting a huge variety of projects from solar-system studies to cosmology it is equipped with the world's largest infrared camera. Design and construction has been managed by the UK Astronomy Technology Centre for a Consortium of 18 UK Universities led by Queen Mary, University of London.
As the acronym suggests it can be enhanced by an optical camera at a later stage; VISTA stands for Visible and Infrared Survey Telescope for Astronomy. Proposed projects for this world-class telescope range from measuring the galaxy's population of brown dwarf stars to constructing a 3D map that covers about 5 percent of the entire observable universe.
An important part of the telescope's operation is the exchange of different filters in the field of view to alter the waveband to suit the application. Kaydon bearings were selected for this filter wheel mechanism for the infrared camera, primarily to save space. An ability to operate under vacuum in a cryogenic atmosphere of -200degC without lubrication was also a prerequisite.
The bearings and engineering analysis was supplied to the UK Astronomy Technology Centre by RA Rodriguez, the UK factory representatives for the Kaydon Corporation. The chosen bearings are of a type that is now considered an industry standard for achieving high performance in a small space. The duplexed pair has a relatively large 7in bore but an outside diameter of just 7.5in by 0.5in high.
The bearings' weight-saving potential was also beneficial to the filter wheel mechanism design. And as the application could not tolerate grease or oil lubrication these stainless steel angular contact bearings were supplied with lead ion dry film lube.
Sited at the Cerro Paranal Observatory in the Atacama Desert in Chile and operating at an altitude of 2635m, this 4m telescope will become part of the European Southern Observatory's suite of telescopes. Its discoveries will be crucial in optimising European exploitation of southern hemisphere 8m telescope time.
