Feature: The Sky's the Limit for New SOAR Telescope
MSU’s new, state-of-the-art telescope in Chile opens up an incredible array of research opportunities in astronomy and astrophysics.
“Thirteen billion years! Imagine, just imagine, with this instrument we will be seeing the universe as it was almost 13 billion years ago!”
MSU President M. Peter McPherson was awestruck as he captured the fascination of many in attendance at the recent campus dedication of MSU’s newest tool of discovery, the SOAR (SOuthern Astronomical Reseach) telescope. More than 300 people–MSU administrators, faculty, students, alums, major donors, and friends of astronomy–gathered in the atrium of the Biomedical and Physical Sciences building on April 17 to celebrate MSU’s involvement in the SOAR 4.1m telescope project.
Earlier that day, Robert Huggett, vice president for research, and Jack Baldwin and Gene Capriotti, both members of the MSU Dept. of Physics and Astronomy faculty, stood shoulder to shoulder with other dignitaries for the dedication of SOAR in Chile.
Following 30 minutes of viewing displays documenting the construction of the SOAR telescope, and posters illustrating the science that MSU astronomy faculty and students will be carrying out with it, the entire crowd gathered to hear speeches from Dept. of Physics and Astronomy chairperson Wolfgang Bauer, faculty member Timothy C. Beers, Dean of the College of Natural Science George Leroi, Associate Vice President for Research Paul Hunt, Provost Lou Anna Simon, and President M. Peter McPherson. Following this ceremony, all gathered in the BPS atrium once more for the unveiling of the SOAR Remote Observing room, which will be the primary link between MSU astronomers and the telescope, 10,000 miles away on Cerro Pachon, Chile, a 9000 foot mountain in the foothills of the Andes Mountains.
SOAR is a joint project between MSU, the University of North Carolina at Chapel Hill, the country of Brazil and the National Optical Astronomy Observatories. The nation of Chile is a de facto partner, since it has provided the land on which SOAR is built. More than 10 years in the making, the SOAR telescope features some of the world’s most advanced technology, including adaptive optics that correct for both image motion and distortion due to atmospheric disturbances, and the Spartan Infrared Camera, designed and built at MSU. The total cost of the project is $43 Million, with MSU providing $6 million of that cost. MSU astronomers will have 12.5 percent of the available viewing time per year, or approximately 40 nights per year for the next two decades.
The primary first generation instrument of SOAR will be the Spartan Infrared Camera, designed and built at MSU under the leadership of associate professor Edwin Loh. This $1.6 Million instrument will provide the most detailed, crisp, images from SOAR in the infrared portion of the spectrum. The clarity of the images from this amazing instrument will rival the quality of those generated in the optical with the Hubble Space Telescope.
The "heart and soul" of every telescope is its optics, the mirrors that receive the light from the objects astronomers seek to study, and direct it to the instruments that have been designed for this purpose. The SOAR optics system comprises three mirrors—the 14 foot (4.1m) diameter primary mirror, mounted in a specially designed mirror cell with numerous high-frequency activators that allow for computer-controlled correction of mirror distortions, a three-foot secondary mirror, mounted near the top of the telescope, which receives light from the primary, and finally, a small tertiary mirror, which incorporates a high-speed "tip-tilt" correction for atmospheric distortions, and also sends the light received from the secondary mirror into the SOAR instruments, which are mounted on the periphery of the telescope like fisherman around a pond.
The SOAR mirrors were manufactured from Corning Ultra Low Expansion (ULE) glass in Corning's New York glass works. The ULE glass resists changes in size with changing temperature, an important consideration for astronomers due to the wide temperature ranges experienced on the mountaintop. Although the primary mirror is 14 feet in diameter, it is only about four inches thick! Such a thin mirror is used in order to keep it in temperature equilibrium with ambient air on the mountain. This prevents bubbles of hot air from forming in the light path and distorting the images. Polishing of the mirrors was accomplished at the Goodrich Corporation (formerly Raytheon) in Danbury, CT. Goodrich was also the primary contractor for the final assembly of the SOAR telescope optics.
Once the optics were approved, they were ready for shipping. In early December 2003, after being trucked from Goodrich to the port at Elizabeth, NJ, the mirrors were loaded into a protected storage area of a large ship bound for South America. This slow journey, through the Panama Canal, and down the western edge of South America, eventually led to the port of San Antonio, Chile, just south of Santiago, the capital. The 400 mile journey northward to Cerro Pachon was completed very carefully by truck in early January 2004.
Once on Cerro Pachon, there still remained one last critical step—application of the reflective coating of aluminum that provides the best possible surface for gathering the incoming light. The SOAR optics were coated using the re-aluminizing facility at the Gemini South 8m telescope, just a few hundred yards from SOAR. This procedure was a complete success—and the final mirrors of SOAR have been shown to reflect greater than 90 percent of all of the light that falls on them, a remarkable achievement. The final mounting of the mirrors into SOAR took place in early March 2004.
There is no doubt that the SOAR telescope is a tool of enormous research capabilities, but what areas of astronomical research will MSU faculty and students be using it to explore? What new questions will they ask, and what new answers will they find? The astronomy group within the Dept. of Physics & Astronomy comprises nine full-time faculty, three post-doctoral research associates, and about 20 graduate students and 30 undergraduates, all of whom are actively seeking to explore the nature of the universe, from the smallest to the largest scales.
Professor Robert Stein studies the nature of the nearest star, our Sun. His five decades of modeling, using detailed computational codes that are capable of representing the flow of radiation from the inside of the Sun, have led to an understanding of the complex bulk motions of its outer layers. These models are essential for astronomers to understand the observations they will make with the SOAR telescope, and other telescopes worldwide, as they decode the messages received from stars throughout the Galaxy.
Assistant professor Edward Brown specializes in the nature of some of the most exotic objects in all of astronomy, the collapsed remnants of stars at the end of their lifetimes, such as white dwarfs and neutron stars. His theoretical research is revealing how matter that falls onto these objects interacts with them, often with dramatic and explosive consequences that are observed in X-ray and gamma-ray emission. Of particular interest are thermonuclear explosions of white dwarf stars, known as type Ia supernovae. The Optical Imager and Spartan Infrared Camera on SOAR will enable Brown to examine the ashes of these explosions for clues about the nature of the explosion.
Professor Timothy Beers studies one of the most fundamental and important areas of modern astronomy and astrophysics, the origin of the elements. His two decades of research have led to the identification of the oldest “still shining” stars in the Milky Way, recognizable because of their extremely low abundances of heavy elements such as iron. These peculiar abundances tell astronomers that the stars studied by Professor Beers must have been born as early as several hundred million years following the Big Bang, the very beginning of our Universe, more than 13 billion years ago. Professor Beers has identified stars which possess measurable lines of the radioactive elements Thorium and Uranium, and which are now being used to obtain “radioactive decay” age estimates of the age of the galaxy, and the universe. Just last year, he was a co-discoverer of the most iron-poor, and hence chemically most primitive, object known in the universe, HE 0107-5240.
Professor Beers works closely with members of the National Superconducting Cyclotron Laboratory on the MSU campus to refine models of how the elements in such stars were formed from the complex nuclear interactions that took place in the first generations of stars. This work has led to the funding of a new $10 Million Physics Frontier Center, JINA, the Joint Institute for Nuclear Astrophysics, a collaboration between Michigan State University, the University of Notre Dame, and the University of Chicago. Professor Beers will be using optical and infrared spectrographs provided by other SOAR partners to continue his searches for the most metal-deficient stars in the Galaxy, and to expand his studies of the elemental compositions of the first stars in the Galaxy.
Professor Horace Smith is a renowned expert in the nature of variable stars, such as RR Lyraes, which astronomers use to provide precision distance estimates of other nearby galaxies, and to calibrate the methods that astronomers employ to determine the size of the entire universe. Smith will be using the SOAR Optical Imager to measure the variations of the brightness of RR Lyraes, and other stars, which can be used to infer their intrinsic brightness, and in turn their distances. With its unfettered view of the nearby galaxies known as the “Clouds of Magellan,” as well as the center of the Milky Way galaxy, studies with the SOAR telescope will provide the basic data needed to calibrate the “yardstick of the Universe.”
Many of the projects carried out with SOAR will depend directly on the aspect of “looking back into time,” seeing very distant objects as they were many billions of years ago because their light has taken that long to travel to us.
Professor Steve Zepf studies the nature of the formation of galaxies throughout the universe similar to our own Milky Way. His primary tools are the globular clusters, dense collections of millions of individual stars, many of which are thought to have formed early in the history of the universe. Professor Zepf’s recent research has demonstrated that globular clusters can also form as a result of the relatively recent collisions of large galaxies, hence he will be using the SOAR Optical Imager, the Spartan Infrared Camera, and SOAR spectrographs to study the nature of galaxy evolution from the distant past to the present.
Associate Professors Megan Donohue and Mark Voit’s laboratory of discovery are the giant clusters of galaxies that form the “backbone” of the structure of the Universe. These collections of hundreds to many thousands of galaxies provide astronomers with their best “fair sample” of how matter is collected on large scales throughout the universe. They are also the home of the mysterious “dark matter”, which, although not visible, accounts for roughly 85% of all of the matter in the universe.[jab1] Their theoretical and observational studies of the giant clusters are being used to constrain the modern paradigm of structure formation in the universe. They will use the SOAR Optical Imager, Spartan Infrared Camera, and SOAR spectrographs to expand the sample of clusters of galaxies with well-measured properties, and better understand both their formation and evolution over the lifetime of the Universe.
Donahue and Voit are well-known co-authors of The Cosmic Perspective, one of the best selling textbooks in use by undergraduate non-science majors at MSU and throughout the world.
Professor Jack Baldwin studies the nature of the most luminous objects in the universe, the quasars and other active galactic nuclei. These objects are powered by the accretion of gas onto supermassive (hundreds of millions of times the mass of the Sun) black holes that are commonly found at the centers of large galaxies. The black holes convert this matter into energy, some of which is found in the visible and infrared wavelengths. Because they are so luminous, quasars serve as “signposts” that can be observed more than half way across the entire universe, more than 12 billion light years away and hence more than 12 billion years into the past. Baldwin will use the Spartan Infrared Camera, as well as SOAR spectrographs, to elucidate the nature of the interaction of the accreting gas with the central black holes, knowledge which astronomers require in order to understand the formation and evolution of these galactic powerhouses.
Professor Edwin Loh will use the Spartan Infrared Camera to discover and analyze spectacular supernova explosions. The supernovae discovered will provide key constraints on the nature of the apparent acceleration of the expanding universe, and the so-called “dark energy” that is thought to provide the source of this acceleration. The “mass equivalent” of the dark energy may account for up to 70 percent of the entire mass-energy content of the Universe.
Many of the most important questions to be answered by MSU astronomers using the SOAR telescope have yet to be asked. This is the nature of research and discovery. With the availability of SOAR, generations of MSU scientists and their students will be given the opportunity to expand human knowledge at the frontiers of astronomy. It is an exciting time for our University, and for MSU Spartans the world over.
author’s note: Timothy Beers is professor of astronomy in MSU’s Dept. of Physics & Astronomy, where he has been on the faculty since 1986. His primary research concerns understanding the nature of the first stars in the universe, and the origin and evolution of the elements. Beers is a co-investigator in the newly funded Physics Frontier Center JINA: Joint Institute for Nuclear Astrophysics.
SPARTAN INFRARED CAMERA
Like the lens of your eye, the SOAR Telescope collects light, and its instruments, like your retina, detect and analyze light. Equipped with MSU’s Spartan Infrared Camera, an infrared-seeing retina, SOAR can see the center of our Milky Way Galaxy though the intervening dust as well as distant galaxies and supernovae, whose light, though emitted in the visible part of the spectrum, has been redshifted by the expansion of the universe into the infrared.
The Spartan Camera, shown here with the vacuum jacket removed to reveal the optics inside, is considerably larger than your retina; it is 2´3´3 ft and weighs 600 lb. The Physics-Astronomy Department designed and built Spartan under the leadership of astronomer Ed Loh.
With its 16-megapixel detector, Spartan will be able to cover a wide area of the sky with superb resolution. The picture below shows a simulated double star under excellent seeing conditions on the left and with SOAR’s tip-tilt correction of atmospheric turbulence on the right.
HOW YOU CAN HELP SOAR
Your name can still go on the Remote Control Observation Room in the Biomedical & Physical Sciences Building, where MSU scientists can measure community
MSU still needs $1.4 million to make the Soar project reality. MSU has committed $6 million to this $43 million project, with university resources covering $2 Million. The College of Natural Science and Dept. of Physics and Astronomy, responsible for the balance, do not want the cost of the SOAR Telescope project to adversely impact the educational quality of any program.
Already halfway there, MSU needs to find the remaining $1.4 million from alumni and friends. Personal commitments from astronomy enthusiasts are critical to making these discoveries a reality for MSU. Funds given to MSU’s SOAR project qualify the donor for membership in University donor recognition clubs and pledges made to the telescope can be paid over a five year period.
For more information or to help support the SOAR Telescope, please contact Suzette Hittner at the College of Natural Science at 353-9855 or hittner@msu.edu.