The use of a laser tracker for initial optical alignment of a solar telescope

Abstract

The Association of Universities for Research in Astronomy, Inc. (AURA) is currently constructing the Advanced Technology Solar Telescope (ATST), a four meter aperture solar telescope on Haleakala in Hawaii, under contract to the National Science Foundation. The ATST will be the world's most powerful solar observatory, poised to answer fundamental questions about the basic processes which govern variations in solar activity. ATST will provide a revolutionary new window on the solar magnetic atmosphere and will be the primary scientific tool for understanding the impacts of variations in the solar output on the Earth's climate. Solar astronomers will use ATST to understand what causes solar eruptions and provide the knowledge necessary to develop space weather forecasting, necessary for protecting or mitigating the potentially devastating societal and economic impacts of solar flares and mass ejections on the nation's space assets, the power grid and communication systems. The ATST optical design contains a four meter aperture off-axis parabolic primary mirror as the collecting element and nine relay mirrors up to one meter aperture to feed multiple scientific instruments. Traditional alignment methods used to position aspheric optics have included use of mechanical jigs, theodolites and alignment telescopes prior to analysis of the image quality.