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Astro*Dictionary by Michael Erlewine





1 article for "Jones, Sir Harold Spencer"

Jones, Sir Harold Spencer [Astro*Index]

(1890-1960) English astronomer.

He wanted to determine an accurate measurement of the distance of the Sun and, thereby, specify a value for the AU (Astronomical Unit), the `yardstick' of our Solar System. In the 1920s, he made precise measurements during occultations of stars by the Moon, from which the solar distance could be derived. Then, in 1931, the planetoid Eros (discovered in 1898) was scheduled to make a close approach to the Earth. No less than 14 observatories in 9 countries participated, about 3000 photographs were taken, and 7 months were spent on the project. Then followed 10 years of calculation, under the direction of Jones. Finally, in 1942, Jones published his result: 93,005,000 miles, a figure which was not improved upon until the radar bounce experiments at JPL in 1961.


Astro*Index Copyright © 1997 Michael Erlewine