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Astronomers band together for more time to observe

Astronomers band together for more time to observe

Thursday, April 15, 2010

A lot of patience, preparation and luck are required for an astronomer to have just one a successful night of observation. Access to the world’s most powerful telescopes is scarce; and once time is secured (typically six or more months in advance), astronomers are at the mercy of the weather when their rare opportunity to use the telescope finally arrives.
SARA telescope
Astronomy researchers in small university astronomy departments or at small colleges sometimes face even greater obstacles when trying to gain access to high-powered telescopes. Research grants can be harder to come by and waits to use telescopes can be even longer. If researchers can get a slot at all, it may be for only a couple of nights per year.

Astronomers from 10 institutions, including Agnes Scott College, have banded together, through a consortium called the Southeastern Association for Research in Astronomy (SARA), to overcome the typical challenges of being an astronomer at a small department or college and have just completed refurbishing and automating a 0.6-m telescope at Cerro Tololo Inter-American Observatory in Chile. With the help of the Chilean telescope and a telescope the group already operates at Kitt Peak in Arizona, each institution in the group can now view the night skies from both the Northern and Southern Hemispheres (occasionally simultaneously) for about 30 days out of the year.

“Schools as small as Agnes Scott College wouldn’t normally have one research-level telescope, much less two,” said Chris De Pree, a professor of astronomy and physics at Agnes Scott College. “This availability of observing time gives the member schools a lot of flexibility in choosing projects.”

In order of membership, SARA’s members include Florida Institute of Technology, East Tennessee State University, Valdosta State University, Florida International University, Clemson University, Ball State University, Agnes Scott College, University of Alabama, Valparaiso University and Butler University. The group was originally formed in 1992 by Florida Institute of Technology, East Tennessee State University, the University of Georgia (which left the group in 2006) and Valdosta State University.

The telescope in Chile was formerly operated by Lowell Observatory in Arizona and was closed by Cerro Tololo in 1996. SARA invested about $250,000 in upgrades to make the telescope remotely accessible over the Internet.

Alone, none of SARA’s members would have been able to acquire and refurbish the telescopes in Chile or Arizona. “This has been a big issue in astronomy for 50 years. There are definitely haves and have nots,” said William Keel, a professor of astronomy and physics at the University of Alabama.

But together, “the 30 astronomy researchers and 10 institutions that make up SARA form a virtual astronomy department that is as large as many major astronomy departments in the U.S.,” said Terry Oswalt, SARA chairman and Florida Institute of Technology professor.

SARA’s success stems from not only being able to pool their resources, but also to acquire excellent facilities for a very low cost.

“We’re able to benefit from someone else’s investment. We’ve managed to phenomenally lower operating costs for a telescope of this size,” Keel said.

For roughly the cost of a few nights of viewing on a very powerful telescope, SARA collaborators instead get about 30 days of time a year. All those extra nights of viewing and the addition of a telescope in the Southern Hemisphere open a host of new opportunities to pursue longer-term and more risky projects.
NGC 5128
“Some level of guaranteed observing time makes deeper observations possible,” De Pree said. “One area of interest for me and my students is making follow up observations of extrasolar planetary transits. These observations require lots of telescope time, and provide valuable information that complements discovery missions like NASA’s Kepler Mission—a space based telescope looking for Earth-sized planets.”

The two SARA telescopes are separated by thousands of miles. “In the same way having two eyes gives depth perception, the two SARA telescopes give us the ability to measure distances and orbits for such objects as potentially hazardous asteroids,” said Terry Oswalt, head of the Physics and Sciences Department at the Florida Institute of Technology. “In addition, because they are at different longitudes, they allow us to stay focused on an object for more than the 10 or 12 hours typical of one site.”

Oswalt studies white dwarf stars, the dense small cores of dead stars that no longer burn hydrogen. He uses some of his SARA observation time to study the flickering that some white dwarfs exhibit. In the same way seismology tells us about the earth’s interior, such flickering can be used to study a white dwarf’s internal structure.

Those who study variable stars (stars with varying brightness as their light reaches Earth, sometimes indicating a nearby star or planet obstructing its light as it orbits) can set an optimal schedule to observe certain characteristics of the star, Keel said. One SARA researcher tracks a variable star of interest once every ten days, something that would be nearly impossible without the flexible telescope access available to members of the group, Keel added.

De Pree and his students at Agnes Scott plan to use a portion of their increased telescope time to detect planets orbiting nearby stars using the transit method. The transit method allows astronomers to determine information about a planet’s mass, atmosphere and orbital period by measuring the brief dimming of the planet’s host star as the planet passes in front of the star. De Pree plans to start with confirmation observations of new planetary detections from the Kepler mission, launched in 2009.

The group’s flexibility is even further improved by their ability to remotely access their telescopes from their labs. Professors and their students can now operate one or both of the telescopes from their university labs on assigned nights, sometimes changing schedules at the last minute to accommodate unexpected opportunities. Dieter Hartmann, a Clemson University professor who studies gamma ray bursts, needs to observe a burst just minutes after it’s reported.

“We can easily trade or share nights in real time,” Oswalt said. “If we get what we need, it’s not unusual for us to call a colleague to take over in the middle of the night. This type of flexibility just isn’t available at more traditional observatories.”

Agnes Scott College educates women to think deeply, live honorably and engage the intellectual and social challenges of their times. Students are drawn to Agnes Scott by its excellent academic reputation, exceptional faculty and metropolitan Atlanta location – offering myriad cultural and experiential learning opportunities. A diverse and growing residential community of scholars, this highly selective liberal arts and sciences college is known for its dynamic and challenging intellectual community. Encouraging students to engage the wider world through study abroad and presenting its curriculum with international context, Agnes Scott College delivers on its promise: The World. For Women.