Observing the solar corona

Prof. Jay Pasachoff observes the solar corona at total solar eclipses. The most recent expeditions, with Williams College undergraduates participating, were to Siberia for the August 1, 2008, total solar eclipse; Tianhuangping, China, for the July 22, 2009, total solar eclipse; Easter Island for the July 11, 2010, total solar eclipse; Queensland, Australia, for the November 3, 2013, total solar eclipse; and Lope National Park, Gabon, for the November 13/14, 2013, total solar eclipse. See Eclipses & Transits


Prof. Pasachoff and Dr. Babcock travel the world to observe occultations of stars by Pluto and other objects in the outer solar system. See Occultation Research

Planetary nebulae

Prof. Karen Kwitter studies the late stages of evolution of old stars like the sun, which puff off their outer layers, forming glowing gas shells called planetary nebulae. She observes their spectra with ground-based telescopes such as the 3.5-meter ARC reflector in New Mexico, and with the Hubble and Spitzer Space Telescopes. Analysis of planetary nebulae spectra can tell us how their parent stars make and disperse chemical elements into space. See Kwitter’s research page

Emission-line stars

Dr. Steven Souza studies young, massive stars that emit excess light in the H-alpha spectral line of hydrogen. The project involves monitoring variations in H-alpha emission over timescales of days to years to help determine the nature of these peculiar stars. He and his students use both our on-campus 0.6-meter rooftop telescope and the 0.5-meter ARCSAT telescope at Apache Point Observatory in New Mexico, operated remotely from campus. See Emission-Line Stars


Prof. Pasachoff works with colleagues at the Harvard-Smithsonian Center for Astrophysics on x-ray studies with the Chandra X-ray Observatory in space.

Cosmic Deuterium

The detection of deuterium and the calculation of a D/H ratio are important tools for determining the baryonic density of the Universe. Prof. Pasachoff directed a project to catalogue four decades of deuterium-related articles. See Cosmic Deuterium