Williams College Scientists Travel to View Solar Eclipse

A Williams College team of faculty and students is preparing to make scientific observations of the total solar eclipse of the Sun that will sweep across the far side of the Earth on Wednesday, March 29. Jay Pasachoff, Bryce Babcock, and Steven Souza of Williams College's astronomy and physics departments are joined by six undergraduates for their astronomical pursuits. The trio has been working together on a series of expeditions, most recently to study Pluto and its moon Charon.

The expedition is on the Greek island of Kastellorizo, a small island in the Dodecanese, east of Rhodes. Aside from Cyprus, it is the farthest eastern point of Europe, so many last-minute eclipse watchers will attempt to get there. The Williams College group will be on site a week in advance, to give them time to set up, test, and align their more than nearly a ton of equipment. They are working closely with Prof. John Seiradakis of the Aristotle University of Thessaloniki, the second largest city in Greece. They are continuing the collaboration they began with joint observations there of the 2004 transit of Venus.

Pasachoff, Babcock, and Souza last observed an eclipse in 2002 in Australia. The total solar eclipses since then have been visible only from Antarctica in 2003 and mid-Pacific in 2005, preventing use of the complex equipment they will be taking to Greece for the 2006 eclipse. The students participating are Megan Bruck '07, Shelby Kimmel '08, Paul Hess '08, Jesse Levitt '08, Amy Steele '08, and Anna Tsykalova '08. Most of the group was able to devote time during Williams's January Winter Study Period to testing equipment, most of which arrived in Kastellorizo before the team.

The eclipse will start at dawn in Brazil, and sweep over Africa from Ghana, Benin, and Togo through Nigeria, Niger, and Chad. Many amateur and professional astronomers will observe from southern Libya. The path of totality will sweep over the Libyan/Egyptian border before crossing the Mediterranean and reaching the Greek island where the Williams team will be. That island is less than two miles off the Turkish coast, where many eclipse watchers will gather. After passing over the middle of Turkey, the path of totality will cross parts of Russia, Georgia, and Kazakhstan, before ending at sunset in northwestern Mongolia. A partial eclipse will be visible from all of Europe and from most of Africa and Asia.

The Williams team will have three minutes to make their observations of the sun's corona, the faint outer halo of million-degree gas that is hidden by the everyday blue sky at times other than those of total solar eclipses. That time is relatively long compared with the approximately 30 seconds each of the previous eclipses.

Two of their experiments involve searching for the mechanism by which the solar corona is heated to millions of degrees by taking rapid series of images with new electronic cameras through special filters. One of the filters passes a narrowly defined color in the green and the other passes a narrowly defined color in the red, each emitted by gas in the corona from iron that has been heated to such high temperatures that it has been stripped of 13 and 9, respectively, of its normal quota of 26 electrons.

A third experiment makes use of a special filter that provides an even more narrowly defined coronal color. This filter, known as a Fabry-Perot, was designed and built by the Johns Hopkins University Applied Physics Laboratory for David Rust, a solar astronomer there. Dr. Rust and his colleague Matthew Nobel will join the Williams team on Kastellorizo. Williams alumnus Rob Wittenmyer '98, now a graduate student in astronomy at the University of Texas, will work with the team on site.

A fourth experiment involves a specially built telescope that matches one now defunct in space on board the Solar and Heliospheric Observatory (SOHO), a satellite built and operated by the European Space Agency and NASA. Both of those organizations have arranged with Pasachoff to receive a digital image immediately after the eclipse, if the eclipse weather is clear, to merge with their own spacecraft images and to distribute to the public. Bernhard Fleck, SOHO project scientist, will be on site with the Williams team.

The Williams expedition will further obtain a wide variety of digital and film eclipse images. Several veterans of previous Williams College eclipse experiments, including Lee Hawkins from Appalachian State University and Jonathan Kern of the Large Binocular Observatory in Tucson, Arizona, will also participate on site. Kern will make images with a special camera modified to flatten the extensive dynamic range of the corona to allow the delicate coronal structure to show on a single piece of photographic film. Robert Lucas of the University of Sydney, Australia, will make telescopic images of the corona using a filter that passes only the green light from thirteen-times ionized iron. They will also be joined by David Hathaway, a solar physicist from NASA's Marshall Space Flight Center. Prof. Marek Demianski of the University of Warsaw, a frequent visiting professor at Williams, will also participate.

In Kastellorizo, the Williams team will be joined by Prof. Seiradakis and two of his students. They will also be joined for the eclipse by Dr. Margarita Metaxa from Athens, who works with Pasachoff on the International Astronomical Union's Commission on Education and Development, and two of her high-school students.

As Chair of the International Astronomical Union's Working Group on Eclipses, Pasachoff maintains a Website at http://www.eclipses.info that links to various eclipse-related resources. With the assistance of Milos Mladenovic of Williams College's Office of Information Technology, he has recently posted a document detailing all the scientific experiments scheduled for various sites in Libya, Egypt, Greece, and Turkey.

For the current expedition, Williams College received a grant from the National Science Foundation. Pasachoff also received an earlier grant from the Committee for Research and Exploration of the National Geographic Society. The new electronic cameras were supplied by an equipment grant to Williams College and MIT from the Planetary Sciences Division of NASA. Additional support is being provided by Sigma Xi, by the Massachusetts Space Grant, by the Rob Spring Fund, and by the Ryan Patrick Gaishin fund. Some of their photographic equipment has been lent by National Geographic and by Nikon.

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On site in Kastellorizo, Greece, Pasachoff will have mobile phones +30 69 45 88 0082 and +30 694 8860964; Seiradakis will have mobile phone +30 697 3667564.

Their telephone number at the Kastellorizo Hotel in Kastellorizo is +30 22460 49044 and, with equipment, at the Megisti Hotel is +30 22460 29372.

March 30-April 1st they will be at the Mediterranean Hotel in Rhodes, +30 22410 24661.

[For international calls from the United States, dial "011 30" for the +30 shown.]

time difference from NY: 7 hours later through March 26; 8 hours March 26-April 1st