The Largest Solar Telescope in the World

DKIST FILMS Daniel K. Inouye Solar Telescope

ATST, Advanced Technology Solar Telescope (Renamed as DKIST)

THE LARGEST SOLAR TELESCOPE IN THE WORLD Crawler Mechanism Crawler mechanism early unit on real scale Main structure fabrication Azimuth mechanism bogies test bench ( Base ring + arch girders)

The DKIST Enclosure is unique in that it positions The Enclosure design contract with cons- Following the completion of the detailed de- truction option was awarded to IDOM in sign, the fabrication of DKIST Enclosure was the optical system’s first aperture stop and tracks June of 2010, completing successfully the launched in May 2012 with the fabrication of design in January 2012. a crawler mechanism early unit. As a solution the suns’s motion with millimeter-level accuracy. implemented for the first time, the crawler The DKIST Enclosure, a large structural- was first subjected to both functional and en- mechanical system approximately 72 ft. durance tests on a real scale test bench. Two crawler units for driving Shutter tracks assembly Secondary Structure DESIGN AND FABRICATION [22m] tall and 87 ft. [26.6m] in diameter, the shutter motion and alignment is one of the observatory’s key subsystems, Simultaneously, the fabrication of long lead providing complete protection for the tele- items like main structure – i.e. the base ring The Daniel K. Inouye Solar Telescope (DKIST), scope and optics. and the two arch girders-, azimuth mecha- formerly the Advanced Technology Solar Te- nism, and control system was launched. lescope (ATST), is a 4-m class domed solar te- In order to accomplish its functions, the When completed, dimensional controls on lescope located at the Haleakalā High Altitude DKIST Enclosure is comprised of a number main structure partial assemblies were suc- Observatory in Maui, Hawaii, funded by the of subsystems, including structure, mecha- cessfully accomplished. National Science Foundation (NSF) and coor- nisms, cladding and ventilation gates, han- dinated by the Association of Universities for dling equipment, control systems, and elec- In parallel with the shutter structures fabri- Research in Astronomy (AURA). trical and pneumatic distribution. cation, the shutter tracks were assembled from machined sectors, preassembled and Being the largest solar telescope in the world, it The Enclosure’s azimuth and altitude systems aligned on the arch girder to make sure they will provide unprecedented abilities to view de- are driven by mechanisms especially designed were accurately positioned so as to ensure a tails of the Sun. Using adaptive optics techno- to perform smooth operations at solar trac- good pointing performance. Other systems logy, DKIST will be able to provide the sharpest king speeds. In particular, the shutter motion like the enclosure cable wraps, the secon- views ever taken of the solar surface, which will is accomplished utilizing an innovative solu- dary structure and modular based façade allow scientists to learn even more about the tion for driving large moveable structures, the were finished as part of the last stages of the Sun and solar-terrestrial interactions. “crawler” mechanism patented by Idom. enclosure fabrication process. 700t Weight 26m Approx. diameter 4m Telescope Aperture 2014 Start of site Assembly 3.052m Altitude ( a.s.l)

AURA DKIST ENCLOSURE Client Haleakalā High Altitude IN NUMBERS Observatory (Maui, Hawai’i) Site FACTORY ASSEMBLY & TESTING

The Factory Assembly started with the ins- Soon afterwards, the first azimuth rotation Delivering the world’s tallation and alignment of the Azimuth Me- was completed and the Main Shutter sepa- largest tracking solar chanism Rail on April 2013 after factory site rate halves were mechanically connected preparation. Soon afterwards, Base Ring using the crawler mechanism on the moto- telescope enclosure. modules with the Azimuth bogies assem- rized half. At this point, the control system Haleakala High Altitude Observatory is a bled were installed in place on temporary commissioning started with the goal of ha- unique site for the astronomical observa- supports and, once aligned, the Arch Girders ving the mechanisms ready for the Factory tion, with superb seeing conditions and were installed and correct assembly verified. Acceptance Tests, while the cladding system dominant clear skies. was being installed. On July 2013, the assembly of the secondary However, the need for being respectful to a structure started. With the vertical and hori- The Test Campaign was divided into two sacred space for native Hawaiians and ca- zontal trussed supporting the position of the sets. The first set, conducted on Decem- reful with a fragile ecosystem with several arch girders, the shutter tracks tolerances ber 2013, included the test on the Enclo- Base Ring modules assembled over Arch Girders installation Assembly of the Secondary structure endangered species, jointly with the lack of were verified. In September, all the shutter sure Structures, Mechanisms and Control the Azimuth Bogies industrial capacity nearby, transport restric- modules were installed in the tracks, inclu- Systems, while the second set, conducted tions and high mountain weather limita- ding the attached mechanisms, i.e. the Rear on March 2014, included the test on the tions constitutes a complex Site to work. Door, Aperture Cover and Aperture Stop. Cladding System and on the Maintenance.

Hence, the main purpose of performing the With the main structures and mechanisms The main mechanisms, altitude and azimu- full Factory Assembly and Testing was to en- assembled, the electrical assembly started in th, shown a very smooth operation at both sure the correct integration and performan- October 2013 and the control system began maximum (2°/s) and minimum (0.004°/s) ce of main structures, mechanisms, control gradually testing subsystems functionality. The operation speeds. Regarding the entrance system, secondary structure, smaller mecha- Enclosure was then lifted from the temporary aperture stop pointing accuracy, the enclo- nisms and cladding system, in order to avoid supports and downloaded to rest on the azi- sure pointing performance is significantly the cost and the risk of the integration of muth bogie wheels. better than the specified requirements. those parts at the Site. Start-up of mechanisms during Modular based cladding system Shutters Modules installed in the tracks Factory Acceptance Tests assembly Thanks to: Gometegui Hilfa Aratz Strunor MSI Grupo KabelSchlepp Observatory Sciences Emetal