Astronomy Bio...George Ellery Hale

Jay Bitterman

George Ellery Hale was born in Chicago on June 29, 1868 to a father of considerable means. He was educated at the Oakland Public School and at Adam Academy in Chicago, and he continued his education at the Massachusetts Institute of Technology to study physics, chemistry, and mathematics.

His interest in Astronomy was enormous even when he was quite young. Through a friendship with the amateur astronomer Sherburne Burnham (1838-1921) he bought a second-hand 4-inch refracting telescope. Through another friendship with Hough (1836-1909) he was able to view the heavens, from time to time through the old 18-inch refractor at the University of Chicago.

Even before he became a student he attempted to construct a spectroscope. When his father bought him a spectrometer he could accurately measured the principal Fraunhofer lines in the solar spectrum. While he was a student he continued his observations and developed the idea of the spectroheliograph, a method of surveying the occurrence of a particular line in the Sun's spectrum. The instrument he constructed did not fit well on to his 4-inch telescope, so his father bought him a 12-inch refractor and also equipped him with a solar laboratory. From 1891 to 1895 he used the University of Chicago's observatory extensively and made improvements to his instruments.

In 1892 Hale was appointed Professor of' Astronomy at the University of Chicago and quickly set about to establish a new observatory. He persuaded C. T. Yerkes, a Chicago industrialist, to donate a large sum of money, to build the 40-inch Yerkes refractor telescope. When it was completed in 1897, Hale transferred his astrophysical instruments from his Kenwood laboratory.

In 1893 he worked with physicists Helmholtz and Planck at the Berlin University of Berlin. However he eventually abandoned his plans to take a doctorate because he never found the time to devote towards this goal. In 1899 he was instrumental in the founding of the American Astronomical Society.

Hale's work on solar spectra motivated him to build a number of specially designed telescopes, the most important of which was the Snow telescope (named after the benefactor, Miss Helen Snow) It was eventually installed on Mount Wilson. Later Hale also sought benefactors to build a 60-inch reflector (completed in 1908) using the mirror blank his father bought. He also managed to persuade J. D. Hooker, a Los Angeles businessman to finance the construction of the 100-inch reflector (completed in 1918).

Meanwhile he surveyed the solar chromosphere as well as the rest of the Sun. In 1905 he obtained photographs of the spectra of sunspots which suggested that sunspots were colder rather than hotter, as had been suspected, that the surrounding solar surface. Three years later he detected a fine structure in the hydrogen lines of the sunspot spectra. By comparing the split spectral lines of sunspots with those lines produced in the laboratory by intense magnetic fields (exhibiting the Zeeman effect) he showed the presence of very strong magnetic fields associated with sunspots. This was the first discovery of a magnetic field outside the Earth. In 1919 he made another important discovery relating to these magnetic fields by showing that they reverse polarity twice every 22-23 years.

From 1904 to 1923 Hale was the Director of the Mount Wilson Observatory but overwork forced him to resign. However, he was not a man to rest, and shortly afterwards he adapted his spectroheliograph to allow an observer to view the spectra directly. This adaptation, which created the spectrohelioscope, involved much more than merely the replacement of photographic film by any eyepiece.

As is evident from his creation of numerous telescopes and observatories, Hale was a highly successful organizer. At one time he was elected to the governing body of Throop Polytechnic Institute in Pasadena, and through his influence this initially little known Institute with a few hundred students developed into the California Institute of Technology, now famous throughout the world for its research and scholarship.

He persisted in pursuing his goal of constructing a 200-inch telescope on Mount Palomar. Through his efforts he managed to secure the vast amount money from the Rockefeller Foundation. Although he died on February 21, 1938, not seeing the completion of his greatest dream, the telescope was completed and dedicated to him in 1948.

Published in the June 2000 issue of the NightTimes