The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) is unique as, apart from protecting the telescope and its instrumentation from the weather, it holds the entrance aperture stop and is required to position it with millimeter-level accuracy. The compliance of the Enclosure design with the requirements, as of Final Design Review in January 2012, was supported by mathematical models and other analyses which included structural and mechanical analyses (FEA), control models, ventilation analysis (CFD), thermal models, reliability analysis, etc. During the Enclosure Factory Assembly and Testing the compliance with the requirements has been verified using the real hardware and the models created during the design phase have been revisited. The tests performed during shutter mechanism subsystem (crawler test stand) functional and endurance testing (completed summer 2013) and two comprehensive system-level factory acceptance testing campaigns (FAT#1 in December 2013 and FAT#2 in March 2014) included functional and performance tests on all mechanisms, off-normal mode tests, mechanism wobble tests, creation of the Enclosure pointing map, control system tests, and vibration tests. The comparison of the assumptions used during the design phase with the properties measured during the test campaign provides an interesting reference for future projects.
The Advanced Technology Solar Telescope (ATST) is a 4-m class solar telescope to be built in Haleakala Observatory
in Maui (HI). It will be the largest solar telescope in the world, with unprecedented abilities to view details of the Sun.
Using adaptive optics technology, ATST will be able to provide the sharpest views ever taken of the solar surface. It is
expected that the 4-meter class telescope will have a significant impact on the study of stellar magnetic fields, plasma
physics and astronomy, allowing scientists to learn even more about the Sun and solar-terrestrial interactions.
Apart from the traditional weather protection functions, ATST Enclosure supports the telescope Aperture Stop which
must be accurately positioned to fully illuminate the primary mirror, while preventing insolation of any other system
components. This positioning is performed by the enclosure shutter (altitude) and azimuth mechanisms. In order to
evaluate the positioning capabilities of both mechanisms and verify the structure-mechanism-control interaction of the
involved systems a dynamic coupled model has been created.
On the other hand, the skin of the enclosure is thermally controlled to avoid the "enclosure seeing" by rejecting solar
radiation and keeping its surface temperature as close as possible below the ambient temperature. The thermal control is
achieved by a set of water cooled plate coils. The cooling fluid flow is controlled to achieve the desired reference
temperature. The performance of the system is being analyzed by means of mathematical model with couples the
thermal radiation analysis and the control system performances.