Completed in 1993 and 1996, the two WMKO telescopes located near the summit of Mauna Kea operate nearly 365 nights per year gathering data supporting cutting edge astronomical research. Astronomers will wait months just for the opportunity to operate the telescope for a handful of hours, and even a day of lost observations is crucial to the astronomy community.
As with other large, ground-based telescopes of this age, maintenance is key to assuring peak performance. A recent check-up revealed that over time, the steel journal that supports the 300-ton Keck 1 telescope had been experiencing deflections that, if unchecked, could impact the performance of the telescope. Therefore, when engineers at WMKO began planning for an outage for maintenance work, they needed to be sure that the scope of repairs that were planned would be sufficient to correct the journal deflections and allow continued use of the telescope for years to come.
Based on our experience with similar large-scale foundations for deep- space antennas, CTLGroup was retained to study deflections of the steel journal and overall performance of the telescope foundation.
Our scope of work began with a field investigation that consisted of visual observations, instrumentation of the steel journal and supporting foundation, data gathering during operation of the telescope, and gathering of core samples of the journal grout bed and concrete foundation. CTLGroup then performed laboratory testing of core samples including compressive strength testing, elastic modulus testing, and petrographic examination.
Lastly, our team created an analytical model to compare data gathered during field trials with those predicted analytically, as well as developed recommendations for the scope of needed maintenance work.