High atop a mountain located 55 miles outside of Tucson, Arizona, on a tiny site in the Tohono O’odham Nation, hardly big enough to accommodate our equipment, Sundt’s crews constructed the housing and dome for the 150-inch Mayall telescope on Kitt Peak – one of the largest telescopes in the Western Hemisphere at the time of its construction. To prevent vibration from the ground, strong winds or the movement of the rotating dome that rests on top of the housing, the telescope rests independently from any part of the base or 500-ton dome.


To accomplish this, we constructed a concrete “pier” 92 feet high and 35 feet in diameter. It was poured in one continuous operation, which lasted more than five days, using Sundt-built slip forms and containing 611 cubic yards of job-mixed concrete. Surrounding the pier is the housing structure made up of ten steel hexahedrons, each weighing 25 tons; this structure supports the housing and rotating dome. The hexahedrons were fabricated of steel pipe in Phoenix and then hauled up the mountain by truck.


To accommodate the rotating mechanism, a giant circular drum girder was built on top of the hexahedrons.


A number of important discoveries have been made in the decades since Kitt Peak National Observatory was created, and many thousands of budding and amateur astronomers have had the opportunity to explore their curiosity and learn more about the universe through its facilities and programs.


WIYN Consortium, Inc.


Mayall Telescope Kitt Peak