Viewing the Heavens From the Center of the Universe
While the late Richard Gillis was mayor of Ashland from 1977 to 1990, he called the town the "Center of the Universe." The phrase stuck and is still being used today. Town officials display the slogan on their business cards and there is even a brewery in Ashland called Center of the Universe.
“He came to Randolph-Macon as a student and never left,” said George Spagna, Ph.D., himself a former Ashland mayor and current member of the town council.
It is fitting that Spagna is a councilman in the town that calls itself "Center of the Universe" because he teaches astronomy at Randolph-Macon Collegein Ashland and directs the Keeble Observatory on the college campus, with the help of student assistants. The observatory is named in honor of William Keeble, Ph.D., who taught astronomy at the college from 1919 until 1952.
“The college has been teaching astronomy since 1873,” Spagna said. The original observatory was built to house a telescope donated in 1960 and for astronomy courses and advanced physics students interested in astronomy.
Visitors enter the observatory from a walkway connected to the second floor of the college’s science center.
The original observatory was torn down in 2016, and a new observatory dedicated in November 2017. It houses a state-of-the-art $95,000 telescope that uses a 40-centimeter, or 15.75-inch, diameter mirror to collect and focus light from distant objects in the solar system and beyond. The Keeble observatory is the only observatory in central Virginia open for public viewing.
Mirror telescopes also called reflecting telescopes, have several advantages over refracting telescopes that focus light using lenses, Spagna said. Refracting telescopes are the type used by Galileo to view the heavens, first in 1610, and these are still used by some stargazers.
“They have disadvantages, one of which is that they are subject to aberrations that can be gotten rid of with reflecting telescopes,” he explained. “They are subject to chromatic aberrations, which separates light into colors,” producing a rainbow effect.
An eyepiece is used on the telescope to view the skies directly.
A camera or other instruments can be attached to the Randolph-Macon telescope. An eyepiece is used for direct viewing. The eyepiece is especially useful during public viewing sessions.
“I rely on student assistants for all public viewing,” Spagna said, so viewing schedules are limited, usually to once a week when school is in session. The viewing schedule is available online.
“Viewing isn’t good in the summer around here. It’s too humid. Winter is better because the atmosphere is more stable and there’s less water vapor,” he said. Spagna advises people who want to visit the observatory to check the college’s Clear Sky Chart, which predicts weather-related viewing conditions several days in advance. The chart predictions are valid within about a 10-mile radius of the campus, he said.
“I will tell you it’s not 100 percent accurate, but it is a useful tool. The Clear Sky Chart is more useful over the short term than long term. People might want to check in the middle or late afternoon if they want to come up that evening,” Spagna said.
Most observatory visitors are interested in viewing objects in the solar system such as the moon or planets but the telescope is capable of seeing at a much greater distance, according to Spagna.
“Several million light years,” he said. “How far out you can see depends on viewing conditions and the brightness of the object you are looking for relative to the background of the sky.” A light year is the distance light travels in one year or about 6 trillion miles. That’s 6 followed by 12 zeros.
News media recently reported the first photographs taken of a black hole. Spagna emphasized that a black hole itself cannot be seen or photographed because it is an area of space so dense that light cannot escape. What is visible in these photographs is not the black hole, he said. “It is the shadow of the black hole.”
While the Randolph-Macon telescope cannot photograph the news-making black hole, “We could see the galaxy in which it is located,” according to Spagna. That galaxy, called M-87, is a little larger than the Milky Way galaxy.
Spagna is interested in finding innovative ways to teach astronomy and has developed methods to help teach a course to a blind student.
“He really wanted to take a science course, but all the lab courses require that you see something. In cooperation with the student, who knew better than I, we developed a tactile equivalent to what the lab students were doing,” Spagna said.
With the help of a student assistant, Spagna built models the blind student could touch, which related directly to what a sighted student would encounter in the laboratory. For example, one model allowed the student to identify chemical elements from the spectrum of colors produced by a spectrograph.
“I like to encourage curiosity. The more people ask questions without preconceived ideas of what the answer is, the closer you get to understanding how science is done,” Spagna said.