Ephs in Aruba observe eclipse

During the total eclipse on Feb. 26, Professor of Astronomy Jay Pasachoff led a team of Williams students and scientists in observing and researching the heating of a solar corona. The experiments ranged from searching for rapid oscillations in the corona, mapping the temperature of the corona and imaging the solar corona during the eclipse with the same processes as the Solar and Heliospheric Observatory (SOHO).

On Campus

Telescopes were set up in the Science Quad to view the partial eclipse visible from Williamstown, and students and staff viewed the eclipse from Baxter Lawn as well, using special filters to look directly at the sun.

Professor of Astronomy Karen Kwitter said, “I was working in Washington D.C. , but I did take a break from work to go out and see the eclipse.” During the time that most of the astronomy staff was in Aruba, Kwitter was the only astronomy staff member in the department on campus.

In Aruba

“The eclipse was a fantastic experience, with the clouds that had plagued the partial phases parting about 15 minutes before totality. We were then able to observe the three minutes of totality in a very clear part of the sky,” Pasachoff reported in the Science at the Eclipse press release.

It was Laura Brenneman’s ‘99 first eclipse, and although she spent much of her time manning cameras she says that, “Totality itself was a fairly intense experience— I have never seen anything like it. There were two TV crews up there with us, a group of alums and other spectators down on the lawn in chairs with instructions not to use cameras with flashes, and then us: the frenzied scientists running around hopping over things and snapping pictures.”

The first experiment, supervised by Timothy McConnochie’98 and Bryce Babcock, physicist and coordinator of the Bronfman Science Center, employed techniques developed by Pasachoff to observe the “coronal green line.” This line is an area of the corona that emits a strong light with extremely fast time resolution. Jonathan Kern, an opticts designer, made and designed the optical path for this experiment. He also specially graded an image showing coronal structures, which took into account the wide range of coronal intensities.

The second experiment, which mapped the temperature of the corona, will have to be repeated at the next eclipse due to power failure prior to the eclipse. The experimenters Lee Hawkins, instructor at Wellesley College, and Caroline Artacho-Guerra , from Bryn Mawr College, would have used a technique comparing electronic images of the corona taken at ultraviolet wavelengths.

Eric Plesko, a Williams Alumnus, who also traveled with the observation and research team, measured winds persisting through the eclipse at over 30 knots and a drop in temperature of about 10 degrees during totality.

“We were doing all our experiments and photography from the roof of our condominium, and since the wind on the island was so strong every day, we had to erect wind shelters for the two experiments that were being run,” Brenneman said.

With the sponsorship of the National Geographic Society, Stephan Martin, instructor of Astronomy at Williams, supervised the last experiment, which yielded seven images of the eclipse in totality.

“Being my first total eclipse, the experience of it was absolutely incredible. Pictures and video can show a great deal, but they just don’t compare to the experience of seeing it live,” Martin said. “We put in a lot of hard work, working days and nights to get things ready and the momentum just kept building up to the eclipse. My experiment was to take wide-field images of the solar corona to support observations taken at the same time by the SOHO spacecraft. It went very well and I have a lot of good data. After [the data] is analyzed I hope the scientists working with SOHO will find it very useful.” This experiment was done in collaboration with Dr. Guenter Brueckner of the Naval Research Laboratory, who is head investigator of LASCO (Large Angle Spectrographic Coronagraph).

Jay Pasachoff is Field Memorial Professor of Astronomy and Director of Hopkins Observatory. He also works as Chair of the Working Group on Eclipses of the International Astronomical Union and as Chair of the Astronomy Division of the American Association for the Advancement of Science. Pasachoff is also the author of The Peterson Field Guide to Stars and Planets.

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