- Hale , George Ellery
- (1868–1938) American astrophysicistHale's father, William Hale, was a wealthy manufacturer of elevators in Chicago, Illinois, who stimulated in his son an early interest in designing and making his own instruments. This interest was directed to astronomy by Sherburne W. Burnham, a neighbor and passionate observer of double stars, and increased during his four years at the Massachusetts Institute of Technology, where he studied physics. He built a solar observatory, financed by his father, at Kenwood, Chicago, and after graduating in 1890 became its director. In 1892 he was appointed assistant professor and later professor of astrophysics at the new University of Chicago and from 1895 to 1905 he was director of the university's Yerkes Observatory. From 1904 to 1923 he was director of the newly established Mount Wilson Observatory in California. The last 15 years of his life were spent organizing the equipping and building of the Palomar Observatory in California and in the pursuit of his solar researches in his private observatory in Pasadena.Hale was undoubtedly one of the key figures in 20th-century astronomy. He saw very clearly and very early that astronomy could only develop if much more powerful telescopes were constructed. Thus with great vision and enormous persistence and energy he spent 40 years acting as midwife to a series of bigger and bigger telescopes. His insight was clearly justified for it was with his telescopes that Harlow Shapley, Edwin Hubble, and many others made their observations.His first triumph came when he persuaded Charles T. Yerkes, a Chicago trolley-car magnate, to provide $349,000 to build a 40-inch (1-m) refracting telescope for the University of Chicago. This was and still is the largest refractor ever built. It was first used in 1897. He was soon anxious, however, to build a large reflecting telescope. In 1896 his father acquired a 60-inch (1.5-m) mirror but the University of Chicago was unable to fund its mounting. Hale once more started raising money. This time he interested the Carnegie Institution of Washington in financing the Mount Wilson Observatory. The observatory was founded in 1904 and the 60-inch reflector eventually went into use in 1908. In 1918 this superb instrument was surpassed by the 100-inch (2.5-m) Hooker telescope, largely financed by a Los Angeles business man, John D. Hooker. For 30 years this was the world's largest telescope and it revolutionized astronomy.Hale had resigned from his directorship of Mount Wilson Observatory in 1923 on the grounds of ill health but lost little time in seeking to interest the Rockefeller Foundation in building a reflecting telescope that would be the ultimate in size, 200 inches (5m) across, for Earth-based instruments. In 1929 it was finally agreed that $6 million would be donated for this purpose to an educational institute, the California Institute of Technology, rather than the Carnegie Institution. Hale became chairman of the group directing the planning, construction, and operation of the instrument that was to become his masterpiece.Thus there began an epic struggle to complete the 200-inch telescope, which was to take nearly 20 years. The first mirror made from fused quartz proved to be a $600,000 failure. Hale next tried Pyrex and the first experimental 200-inch disk cast proved satisfactory. The actual casting was made in December 1934 when the 65 tons of molten Pyrex began its carefully controlled 10 months' cooling. The mirror managed to survive the flooding of the factory, which necessitated shutting down the temperature control for three days, and its long journey in the spring of 1936 from Corning, New York, to California at a maximum speed of 25 mph. The grinding of the mirror was interrupted by the war and took so long that Hale had been dead for nine years when the instrument was finally commissioned as the Hale telescope in 1948. It was set up at the specially constructed Palomar Observatory, which together with the Mount Wilson Observatory was jointly operated by the California Institute of Technology and the Carnegie Institution. The two observatories were renamed the Hale Observatories in 1969. The Hale telescope was the world's largest telescope until the Soviet 6-meter (236-in) reflector went into operation in 1977 but is still considered by many to be the world's finest.Hale was not just a highly successful scientific entrepreneur for he made major advances in the field of solar spectroscopy. As early as 1889 he had conceived of his spectroheliograph, an instrument that allowed the Sun to be photographed at a particular wavelength. He also designed an appropriate telescope to which it could be attached. In 1908 Hale made his most significant observation. He found that some of the lines in the spectra of sunspots were double. He realized that this demonstrated the presence of strong magnetic fields in sunspots, being due to the effect discovered by Pieter Zeeman in 1896, and was the first indication of an extraterrestrial magnetic field.
Scientists. Academic. 2011.