Initial Optical Alignment of a Solar Telescope Using Laser Trackers

Abstract

The Association of Universities for Research in Astronomy Inc. (AURA) is currently constructing a 4-m-aperture solar telescope on Mount Haleakala in Hawaii, under contract to the National Science Foundation. The Daniel K. Inouye Solar Telescope (DKIST), formerly the Advanced Technology Solar Telescope (ATST), will be the world's most powerful solar observatory, and is poised to answer fundamental questions about the basic processes which govern variations in solar activity. DKIST will provide a revolutionary new window on the solar magnetic atmosphere and will be the primary scientific tool for understanding the effects of variations in the solar output on the Earth’s climate. Solar astronomers will use DKIST to understand what causes solar eruptions and provide the knowledge necessary to develop space weather forecasting. This could facilitate protecting or mitigating the potentially devastating societal and economic effects of solar flares and mass ejections on the nation’s space assets, the power grid, and communication systems. The DKIST optical design contains a 4-m-aperture, offaxis parabolic primary mirror as the collecting element, and nine relay mirrors with up to a 1-m aperture to feed multiple scientific instruments. Traditional alignment methods used to position aspheric optics have included the use of mechanical jigs, theodolites, and alignment telescopes prior to analysis of the image quality. Laser trackers and coordinate measuring machines (CMMs) are now provid