The Ancient Art of Astrometry

  • Bruce Dorminey


The best hope of finding Earth-like planets around Sun-like stars lies not in Doppler spectroscopy, stellar occultation, water maser detection, or even direct imaging via telescopic ground arrays: it’s in the ancient art of astrometry. Astrometry has long been a tedious and painstaking method of measuring a star’s position, distance, and its proper motion (essentially its movement across our line of sight). In the second century B.C., without the benefit of binoculars or a telescope, the Greek astronomer Hipparchus spent years producing a catalog of over 1,000 star positions. Almost two millennia later, in 1718, Edmund Halley (whose name would later become inextricably linked with the comet) found that three stars—including Arcturus, a northern star that Hipparchus had recorded—had changed their positions on the sky by several fractions of a degree. Halley compared his findings against measurements compiled by Ptolemy, the Egyptian astronomer, who had assembled the work of Hipparchus and others in the Almagest, an astronomical compendium published two centuries after the birth of Christ. Halley’s assumption that the stars must be moving across our line of sight marked the birth of modem astrometry.


Proper Motion Photographic Plate Geostationary Earth Orbit Naval Observatory Target Star 
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  1. 1.
    Dick, Steven J. 1996. The Biological Universe: The Twentieth-Century Extraterrestrial Life Debate and the Limits of Science. New York: Cambridge University Press: 186.Google Scholar
  2. 2.
    Bamard’s Star.“ Department of Physics, University of Durham, U.K.,
  3. Kelleher, Florence M, Florence M. “Edward Emerson Bamard. (April 2, 1997 ).
  4. 3.
    Kaler, James B., astronomer, University of Illinois, Urbana-Champaign. Interviewed on January 14, 2000.Google Scholar
  5. 4.
    Heintz, Wulff, astronomer emeritus, Swarthmore College, Pennsylvania. Interviewed on March 23, 2001.Google Scholar
  6. 5.
    Schilling, Govert. “Peter van de Kamp and His ‘Lovely Bamard’s Star.” Astronomy (December 1985): 26.Google Scholar
  7. 6.
    Gatewood, George D., astrometrist, Director of Allegheny Observatory, University of Pittsburgh. Interviewed on October 27, 1999.Google Scholar
  8. 7.
    Lippincott, Sarah Lee, retired director Sproul Observatory, Swarthmore College, Pennsylvania. Interviewed on May 10, 2000.Google Scholar
  9. 8.
    Seidelmann, Ken, Chairman of the FAME science team, U.S. Naval Observatory. Interviewed on May 25, 1999, at Dana Point, California.Google Scholar
  10. 9.
    Perryman, Michael, astronomer and ESA GAIA study scientist, ESTEC, the Netherlands. Interviewed on October 29, 1999.Google Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • Bruce Dorminey
    • 1
  1. 1.ParisFrance

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