Construction of the telescope was funded by the National Science Foundation, as a prototype for a planned astronomical interferometer at Owens Valley. The interferometer was to incorporate eight dishes moving on rails, positioned up to 5 miles (8.0 km) apart. The 40-metre (130 ft) diameter prototype was completed in 1968, but by the end of the decade plans for the interferometer were cancelled in favour of the Very Large Array.
In 2007 the telescope was re-purposed for a dedicated blazar monitoring campaign, in support of the Fermi Space Telescope which launched in 2008 and observes blazars in gamma rays. As of 2018[update] the telescope takes regular measurements of over 1800 blazars, by observing each one at 15 gigahertz (2.0 cm) twice a week.