At Home in a New Dome
You can also watch a time-lapse video of the installation of the dome.
A computerized, 24-inch reflecting telescope will soon find a home in a new dome atop Swarthmore's science center.
Both are part of the Peter van de Kamp Observatory, made possible by a grant and a gift to the College. The telescope was funded by a $300,000 grant from the National Science Foundation (NSF), capping a six-year-long effort by Eric Jensen and David Cohen, both associate professors of astronomy, to bring a new instrument to Swarthmore. The dome was the gift of an anonymous alumna.
Assembled over several days in September, the dome was hoisted onto the science center roof by a four-story crane. The telescope, to be installed in time for the spring 2009 semester, will be used to train students in observational techniques, allow them to pursue their own research projects, and become part of the Department of Physics and Astronomy's advanced laboratory program for physics majors.
The telescope, whose mirror measures 24 inches in diameter, will be equipped for astronomical research using spectroscopy—an unusual capability for a small liberal arts college.
"Spectroscopy is studying light that is broken up into its different colors, like using a prism to spread out the different colors that make up white light," Jensen explained. "Doing this lets us see the "fingerprints" of different chemical elements, since different elements emit and absorb light of different colors. This lets us measure the physical conditions in stars—what they are made of, what their temperatures are, and so on.
"The shift of these patterns to slightly different wavelengths lets us determine how fast things are moving," he continued, "just as you hear a train whistle have a slightly higher pitch when it is approaching you and a lower pitch as it is receding. So too for light. This effect, called the Doppler shift, can be seen in the spectra of stars, letting us figure out how they are moving through their galaxies, or whether two of them are moving in orbit around each other."
For research and teaching, the new telescope will supplant the 96-year-old, 24-inch refracting telescope in the Sproul Observatory. The old instrument will remain in place and continue to be used for monthly public viewing, weather permitting.