Construction of the Hale Telescope and Palomar Observatory was financially supported by the Rockefeller Foundation in three separate grants to the California Institute of Technology totaling $6.6 million.
The initial $6-million pledge to support the 200-inch telescope construction was made by the Rockefeller-funded International Education Board, and communicated by Board President Wickliffe Rose to Caltech in mid-1928. The grant resulted from an extensive series of communications between Rose and George Ellery Hale, and also involved important support from Foundation Director for Natural Sciences Max Mason, Carnegie Institution Board Chair Elihu Root, as well as the blessing from philanthropist John D. Rockefeller, Jr. The grant provided for construction of the 200-inch telescope and the observatory compound, and the ownership of both by Caltech, who would also host an astrophysical laboratory in Pasadena. The Palomar grant was one of the largest single grants awarded by the Foundation; adjusted for inflation the value of the 1928 grant is approximately $90 million in 2020.
With the long delays associated with World War II, accumulated project costs exceeded the initial grant amount, and the Rockefeller Foundation made supplemental grants following the war totaling $550,000 to facilitate telescope completion.
The telescope was dedicated to Hale’s memory in June 1948. Rockefeller Foundation President Raymond Fosdick opened the dedication ceremony. Fosdick spoke to the Foundation’s commitment to the pursuit of knowledge and truth, and framed against the recent war experience, the hope that knowledge would serve the peaceful progress of all humankind.