The Total Solar Eclipse of December 4, 2002

Scientific Experiments at the 2002 Total Solar Eclipse:
The Williams College Expeditions

The next total solar eclipse will occur on December 4, 2002. It will cross southern Africa (parts of Angola, Botswana, Zimbabwe, South Africa near Kruger Park, and Madagascar) during the early morning during the rainy season, and will then head out over the ocean. It will reach land near sunset in Ceduna, Australia, on the Great Australian Bight on the south coast and about 780 km west of Adelaide. The eclipse will end inland, past Woomera, not many minutes later.

Williams College will launch a scientific expedition to study the solar corona during the eclipse. Approximately a dozen Williams College undergraduate students will participate, in addition to Prof. Jay M. Pasachoff, Dr. Bryce Babcock, and possibly Dr. Steven Souza and Lee Hawkins. Alumus Rob Wittenmyer will also participate.

Pasachoff, chair of the Working Group on Eclipses of the International Astronomical Union (IAU), will be observing his 35th eclipse. He chairs the Subcommittee on Public Education at the Time of Eclipses of the IAU's Commission on Astronomy Education and Development. He wrote the "Peterson Field Guide to the Stars and Planets" in addition to astronomy texts. He is co-author, with Leon Golub, of the trade book "Nearest Star: The Surprising Science of Our Sun," published in 2001 by Harvard University Press. See for IAU-related Web pages, and for book Web pages.

During the 1998 total eclipse in Aruba, the 1999 total eclipse in Romania, and the 2001 total eclipse in Zambia, the Williams expeditions conducted several experiments and took many additional photographs and electronic images and videos. One of the experiments mapped the temperature of a quadrant of the sun's corona, the outermost layer of its atmosphere, which can attain four million degrees Fahrenheit (about two million Celsius) though its surface is only 11,000 degrees Fahrenheit (about 6,000 Celsius).

A second experiment was conducted in collaboration with scientists at the Harvard-Smithsonian Center for Astrophysics, NASA's Goddard Space Flight Center, and the U.S. Naval Research Laboratory. The Williams group took images of the solar corona during the eclipse for comparison with images captured by a rocket launched by Leon Golub of the CfA and with spacecraft images from the Extreme-ultraviolet Imaging Telescope and the Large Angle Spectroscopic Coronagraph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO) in space. Daniel B. Seaton, a Williams student now at the CfA, continues to work on the reduction of these data.

In a third experiment, the Williams scientists measured the polarization of the outer corona for comparison with measurements from the LASCO and Ultraviolet Coronagraphic Spectrometer aboard SOHO. The UVCS observations are in collaboration with scientists from the Harvard-Smithsonian Center for Astrophysics.

A fourth experiment, to look for waves in loops of gas at the edge of the sun, worked well in Aruba and Romania but failed in Zambia when a computer controlling its electronic detector stopped accepting commands. The waves would be a sign of a method of coronal heating. The Williams team is especially looking forward to new data from this experiment in Australia.

A series of Williams College thesis students have worked on the eclipse results, including Timothy McConnochie '98 (now a graduate student in astronomy at Cornell), Kevin Russell '00 (Fulbright scholar in astronomy/physics and now a graduate student in international affairs at Johns Hopkins), Daniel Seaton '01 (now a research assistant at the Harvard-Smithsonian Center for Astrophysics), Gabriel Brammer '02 (now a data analyst at the Space Telescope Science Institute), and David Ticehurst '03 (who is still at Williams and who is hoping for new data).

Many of the images from past eclipses have been assembled into mosaics by Wendy Carlos. See, for example,

The expeditions have been supported by the National Science Foundation, the National Geographic Society, the Keck Northeast Astronomy Consortium, the Massachusetts Space Grant Consortium, the Science Laboratories at Williams College, and the Safford Fund, Brandi Fund, and Rob Spring Fund at Williams.

The group spends months planning and over a week setting up and testing equipment on site, all in preparation for the totality. The corona is visible from earth only while the sun is totally eclipsed. For the December 4 eclipse, totality will last only about 34 seconds from Ceduna and the sun will be only 9 degrees above the horizon, though looking over a water. Weather statistics based on past years indicate that there is about a 2/3 chance of seeing totality.

Williams has a rich history of scientific expeditions, including the first ever sent by an American college, in 1835 to Nova Scotia.

Images from past solar eclipse expeditions expeditions are available at

Some of the eclipse equipment has recently been used to observe occultations of stars by Pluto. For a summary of these very successful observations, notably the event of 20 August 2002, see:

Jay M. Pasachoff, Peterson Field Guide to the Stars and Planets (Houghton Mifflin, 2000)
Leon Golub and Jay M. Pasachoff, Nearest Star: The Surprising Science of Our Sun (Harvard University Press, 2001).
Jay M. Pasachoff, Astronomy: From the Earth to the Universe, 6th ed. (Brooks/Cole, 2002)

See also:
Leon Golub and Jay M. Pasachoff, The Solar Corona (Cambridge Univ. Press, 1997).
Jay M. Pasachoff, 1973, "The Solar Corona," Scientific American 229, #4 (October), 68-79.
Donald H. Menzel and Jay M. Pasachoff, 1970, "Solar Eclipse," National Geographic 138, #2 (August), 222-233.
Jay M. Pasachoff, 1992, "The Darkness That Enlightens," National Geographic 181, #5, 36-37.
Fred Espenak and Jay Anderson, NASA Reference Publication for the 2001 eclipse, available through or directly at
Jay M. Pasachoff and Alex Filippenko, The Cosmos: Astronomy in the New Millennium (Harcourt College Publishing, 2001).

Solar science and the rest of astronomy are described in Prof. Pasachoff's texts and other books. See

Professor Pasachoff travelled to Ceduna, Australia, for reconnoitering of the site, and wrote a report of his trip. It is available, with pictures, at

For more information, contact:
Prof. Jay M. Pasachoff
Williams College--Hopkins Observatory
33 Lab Campus Drive
Williamstown, MA 01267.
1 413 597 2105; fax 1 413 597 3200.

Williams News Office:
contact James Kolesar, 1 413 597 4277,
or Jo Procter, 1 413 597 4279

General eclipse web information:, which is the same as,
and, for specific Williams College expedition information: