The Biographical Encyclopedia of Astronomers

2007 Edition
| Editors: Thomas Hockey, Virginia Trimble, Thomas R. Williams, Katherine Bracher, Richard A. Jarrell, Jordan D. MarchéII, F. Jamil Ragep, JoAnn Palmeri, Marvin Bolt

Hadley, John

  • Roy H. Garstang
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-30400-7_564

BornEnfield Chase, Hertfordshire, England, 16 April 1682

DiedEast Barnet, Hertfordshire, England, 14 February 1744

John Hadley made two major contributions to astronomy – the improvement in the reflecting telescope and the invention of the double‐reflecting quadrant. His brother George was the first (1735) to explain the direction of the trade winds as caused by the rotation of the Earth, superposed on an atmospheric circulation (called a Hadley cell) with an updraft near the Equator and downdrafts near latitudes 30° N and S.

Isaac Newton had used a spherical mirror in the telescope that he showed to the public, but he knew that a parabolic mirror would be much better. About 1720, John Hadley, with assistance from his brothers George and Henry, made a speculum mirror with a 15‐cm diameter, a focal length of about 157 cm, and a paraboloidal figure. The telescope was shown to the Royal Society in 1721. Edmond Halley, who had just become Astronomer Royal, and James Bradley, then...

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Selected References

  1. Andrews, A. D. (1993). “Cyclopaedia of Telescope Makers Part 2 (G–J).” Irish Astronomical Journal 21.Google Scholar
  2. Andrewes, William J. H. (ed.) (1996). The Quest for Longitude: The Proceedings of the Longitude Symposium. Cambridge, Massachusetts: Collection of Historical and Scientific Instruments, Harvard University.Google Scholar
  3. Howse, Derek (1997). Greenwich Time and the Longitude. London: Philip Wilson.Google Scholar
  4. King, H. C. (1955). History of the Telescope. London: Griffin.Google Scholar
  5. Warner, Deborah Jean (1980). “Astronomers, Artisans, and Longitude.” In Transport Technology and Social Change: Symposium 1979, edited by Per Sörbom, pp. 131–140. Stockholm: Tekniska Museet.Google Scholar

Copyright information

© Springer Science+Business Media, LLC. 2007

Authors and Affiliations

  • Roy H. Garstang

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