Allegheny Observatory provides view of the heavens
As the trees leaf out and lilies take over after the daffodils have spent their blooms, the dance of spring unfolds on a hilltop in the North Side with panoramic views of Pittsburgh and galaxies some 20 million light years away.
It is the public viewing season at the Allegheny Observatory, where its three domes open on clear nights, offering cosmic slices of the universe.
For open houses, staff members swing a 15-foot-long telescope with the deftness of a major-leaguer warming up before stepping to the plate.
They know where the planets and stars reside and can train a telescope on an object within seconds, offering up the view to a line of visitors eagerly awaiting a chance to see the rings of Saturn for the first time.
“Make sure that you have your socks duct-taped on you feet for this one,” says Lou Coban, an administrator at the observatory, as he describes the spectacular view of Saturn in the spring sky only a mere 815 million miles away from earth.
Come summer, as the earth's rotation reveals another cast of astronomical wonders, Jupiter will be the favored sighting.
But the Allegheny Observatory offers more than a celestial circus.
It's a hub for research, where planets and stars are discovered and scholars develop innovations to more accurately record their work.
The observatory is a destination for researchers, students and tourists alike. It also serves as a final resting place for the ashes of two former observatory directors and some of their family members.
A donation to the university
Wealthy men from Pittsburgh who desired the magnifying power to see “... heavenly bodies near enough to be viewed with greater interest and satisfaction” founded the observatory in 1859. A few years later, they formed the Allegheny Telescope Association, built an observatory on Pittsburgh's North Side and bought their first telescope.
After about five years of recreational viewing — watching planets and the moon — club members lost interest, and the facility fell into debt. The club donated the building and telescope in 1867 to the Western University of Pennsylvania, now the University of Pittsburgh.
Samuel P. Langley, an enterprising scholar and professor of astro-physics at the university, was named the first academic director of the observatory. He used the facility to study sun spots, among other things.
Not exactly celestial in nature, Langley worked on preliminary designs for an aircraft while he was director of the observatory. Later, he developed the “aerodrome,” a flying machine predating the Wright Brothers' invention.
While at Pitt, he secured funding from William Thaw, a wealthy industrialist, to upgrade the observatory's equipment, including an instrument that could record time precisely by tracking the movement of stars.
Aware of the need to keep accurate time for railroads and other industries, the observatory “sold” time to subscribers for about $3,000 a year, enough to pay for salaries and other operational expenses.
That income, along with endowments from a variety of sources, provided continuing support for generations of directors, scholars and students who amassed a great body of research demonstrating the movement of stars, among other things.
An endowment from Pitt's College of Arts and Science now supports the research and operations at the observatory.
The science of the stars
As the observatory's equipment became more sophisticated, so did the scientific discoveries.
In the 1890s, Langley's successor, James Keeler, confirmed that the rings around Saturn were not solid, but particles.
To accommodate more telescopes and research, a new observatory was completed in Riverview Park in 1912.
The Allegheny Observatory continues to be renowned for the “refracting lenses” in its telescopes. These optics capture light in such a way that images are not distorted. The observatory's Thaw refracting telescope is among the most precise instruments in the world for measuring celestial objects.
As a result, research at the observatory has focused for decades on mapping the sky and measuring stellar distances, the masses of stars and the detection of mass objects around stars, according to George Gatewood, director of the observatory.
Decades' worth of glass plates and other images from multiple generations of astronomers are archived in the basement of this historical landmark, ready for retrieval to document, say, a moving cluster of stars.
These clusters are formed in clumps and spread out over thousands of years. Given the observatory's century or so of records, researchers there can track their movement, distance and mass.
“I remember showing a class a chart with which we determined the mass of some stars, and I remember saying, ‘Here is the observation of (astronomer Otto) Struve, and here is the observation of his grandson,' “ Gatewood says. “I knew these people, and here you had five observations of astronomers, and now we know how much these stars actually weighed.
“A lot of astronomy is quick discovery,” says Gatewood, a Pitt professor of physics and astronomy. But the Allegheny Observatory has staying power. “There have been many observatories that have come and gone in the time it takes to measure the mass of one sun,” he says.
Observatory scholars continue to work with scientists at NASA and throughout the world. The observatory has 13 employees who are observers and tour guides.
A number of important contributions to science have been made at the observatory. For example, the E ring of Saturn was discovered using the Thaw telescope in 1960s.
More recently, Gatewood helped confirm the existence of a Jupiter-sized planet -- the nearest planet outside our solar system. Using records from the observatory, Gatewood estimated the mass of the planet to be 1.2 times that of Jupiter. NASA's Hubble space telescope confirmed the findings in 2006.
As Gatewood is set to retire later in the year after more than 30 years of service, he and his wife, Carolyn, are completing research on the distance between the Earth and the Pleiades cluster of stars -- a benchmark from which other distances to stars can be calculated.
“The reason why is that a satellite sent up made a mistake, so now we are redoing it,” Gatewood says of the Pleiades project. And, of course, their research will be based on the historical images captured through the decades on the glass plates at the observatory.
But now that Gatewood is finishing his work, the observatory will focus on something new: asteroids.
“Do you remember seeing those images of Jupiter when it was hit by those comets?” he asks. “So why measure asteroids⢠One of them might hit Earth.”
As Gatewood exits, he notes that the observatory attracts interesting people, in part because it is in the city. Most observatories are isolated, away from urban lights and, consequently, people.
“This place was founded by amateurs and literally put together by the people of Pittsburgh, from children giving their dimes and millionaires with their money,” Gatewood says.
The observatory has been a haven for star-gazers -- amateurs and scholars -- and generations of visitors.
“It's had this mystique when I first came,” Gatewood says. “You feel like you're part of something bigger than you, and that's a very nice feeling.”
Additional Information:
The Allegheny Observatory in Pittsburgh's North Side is offering tours and a lecture series until November.
Friday night tours run through Oct. 31; Thursday night tours end Aug. 21.
The two-hour tours begin at 8 and include a film presentation preceding a walking tour and a look through the 13-inch Fitz-Clark Refractor telescope constructed in 1861.
The observatory also hosts a lecture every third Friday through November featuring astronomers and physicists from Pitt and other institutions. Topics include putting asteroids to use, looking into deep space and the significance of supernovae in creating new stars. The evenings begin with refreshments at 7 with the lectures to start at 7:30, followed by a tour of the observatory.
All events are free, but reservations are required.
To make reservations, call 412-321-2400 between 1 and 5 p.m. Reservations for tours can include as many as 45 people, including school groups. For lectures, the limit is six people per reservation.
The observatory is in Riverview Park at 159 Riverview Ave. For event schedules and details, go to http://www.pitt.edu/
