special event a tent-like membrane was deployed over the dish, which prevented focused visible and infrared light from destroying the secondary mirror assembly. The last observation from the telescope was made on 8 September 2015, and was of Orion KL. Over 100 students from 25 institutions used the CSO for doctoral research projects. Decommissioning In order to get a permit to build the Thirty Meter Telescope project on Mauna Kea, the University of Hawaii had to commit to closing and dismantling three existing observatories on the mountain. The three chosen were the CSO, the UKIRT, and the Hoku Keʻa telescope. Two additional telescopes must also be removed by 2033, but those have not been selected as of 1 April 2019. On April 30, 2009, Caltech announced plans to decommission the CSO, transferring ongoing research to the next-generation Cerro Chajnantor Atacama Telescope (CCAT) in Chile. The plans called for CSO to be dismantled, beginning in 2016, with its site returned to a natural state by 2018. Delays in the environmental assessment and permitting processes have led to postponement of the telescope removal. On 24 January 2019, Robert McLaren, the interim Director of the University of Hawaii Institute of Astronomy, gave an update to state lawmakers and suggested the permitting will be accomplished in 2019 with dismantling and removal taking a year or less. See also Far-infrared astronomy List of astronomical observatories References External links Galaxy Zoo goes observing at the CSO Caltech Submillimeter Observatory website Astronomical observatories in Hawaii Radio telescopes Submillimetre telescopes Buildings and structures in Hawaii County, Hawaii California Institute of Technology buildings and structures