Composite infrared image of Jupiter at right from SOFIA’s first light flight at wavelengths of 5.4 (blue), 24 (green) and 37 microns (red), made by Cornell University’s FORCAST camera during the SOFIA observatory’s "first light" flight. A recent visual-wavelength picture of approximately the same side of Jupiter is shown at left for comparison. (Visible -- Anthony Wesley; Infrared -- NASA/SOFIA/USRA/FORCAST Team) › View Larger Image
SOFIA 2010: The Year in Review
During the past year SOFIA, the Stratospheric Observatory For Infrared Astronomy, achieved the program’s goals and passed the program’s milestones at a pace almost as fast as the observatory can fly.
At the end of 2009, SOFIA’s engineering team succeeded in flying the observatory for more than an hour with the telescope cavity door fully open. Having achieved this success, 2010 began with additional in-flight testing of the telescope cavity door and its software system.
Image right: Faint specks of starlight are reflected by the 100-inch (2.5-meter) primary mirror on NASA’s SOFIA observatory during ground testing of the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST). (NASA/Tom Tschida) › View Larger Image
On Feb. 8, 2010, principal investigator Terry Herter and his team from Cornell University and Ithaca College, both located in Ithaca, N.Y., delivered what would become SOFIA’s first operationally flown instrument, the Faint Object InfraRed Camera for the SOFIA Telescope, or FORCAST. This instrument is a mid-infrared camera that records images in the five to 40 micron range -- five to eight microns, 17-25 microns, and 25-40 microns – depending upon which channels or filters are selected. (By comparison, the human eye sees radiation with wavelengths of 0.4 to 0.7 microns.)
The instrument was delivered to SOFIA’s base of operations at the NASA Dryden Aircraft Operations Facility in Palmdale, Calif., and was quickly set up in one of the facility’s laboratories. In the lab, engineers from the FORCAST team ran the instrument through its paces to verify performance before installing it on the SOFIA telescope.
Achieving “First Light”
“First Light” is a ceremonial milestone in the astronomical community when photons from a celestial object officially travel down a telescope’s tube for the first time. For SOFIA, first light was determined to be the first time a celestial object was imaged at altitude – a little different than a ground-based telescope, but an event certainly worthy of celebration. In the late evening hours of May 25, infrared light that had been emitted from the red supergiant star Antares (Alpha Scorpii) 550 years ago traveled through SOFIA’s telescope and was recorded on the FORCAST instrument.
The observatory’s second target for the evening was the planet Jupiter, which was imaged at wavelengths of 5.4, 24, and 37 microns. The 24 micron wavelength is very hard to see from ground-based telescopes while 5.4 and 37 microns are impossible to see from Earth. The FORCAST instrument looked through the clouds of Jupiter to record heat radiating from the interior of the planet.
Observations of Jupiter were followed by a close look at the galaxy Messier 82 in the constellation Ursa Major. Peering through obscuring clouds of dust and gas in the galaxy, SOFIA captured images of the star-forming heart of the galaxy more than 10 million light years away. The first light flight was not only the first time photons went down the telescope, but was planned as a demonstration of SOFIA’s stability and versatility, imaging stars, planets and a galaxy on the same flight.
Image right: Composite infrared image of the central portion of galaxy M82, from SOFIA’s First Light flight, at wavelengths of 20 (blue), 32 (green) and 37 microns (red). The middle inset image shows the same portion of the galaxy at visual wavelengths. The infrared image sees past the stars and dust clouds apparent in the visible-wavelength image into the star-forming heart of the galaxy. (Visible -- N. A. Sharp/NOAO/AURA/NSF;
Infrared -- NASA/SOFIA/USRA/FORCAST Team) › View Larger Image
“Looking back on this accomplishment, I could not be prouder of our team in their commitment to the project, their dedication to completing the required flight tests, and meeting the first light milestone on schedule,” said NASA SOFIA Program Manager Bob Meyer. “These tasks had to be finished before SOFIA could move from the testing phase to that of a flying observatory, which is about to release world-class astronomical science results.”
Observatory in Operation
After the first light flight, SOFIA entered its “Short Science” observing phase that highlights the capabilities of the airborne observatory. The Short Science program consists of three flights with FORCAST accomplished in late 2010 and three observing flights in spring 2011 with the German REceiver for Astronomy at Terahertz Frequencies, or GREAT, a spectrometer developed by a team from the Max Planck Institute for Radioastronomy in Bonn, Germany, led by principal investigator Rolf Güsten. GREAT will make its initial flight on SOFIA in April 2011. GREAT produces very high-resolution spectra between 60 and 200 microns and has been designed with a beam splitter that enables two channels to be monitored at a time.
Image right: Deutsches SOFIA Institute quality manager Rainer Strecker conducts a final inspection and cleaning of the German Receiver for Astronomy at Terahertz Frequencies, or GREAT, spectrometer’s mounting plate prior to mating with the SOFIA telescope under the watchful eyes of Alvin Mitchell, NASA quality assurance and Rolf Guesten, principal investigator for GREAT. (NASA Photo/Tom Tschida) › View Larger Image
“For scientists, GREAT will provide a new opportunity to study the atmospheres of planets, examine the chemical composition of the interstellar medium, and expand our knowledge of circumstellar disks around young stars,” said Deputy SOFIA Science Mission Operations Director Hans Zinnecker, who is detailed to the SOFIA program from the University of Stuttgart, Germany. “The international collaboration of GREAT and SOFIA delivers one of the most versatile and unique astronomical instruments available for studying the far infrared spectrum. For the foreseeable future, GREAT is the only instrument, ground- or space-based, that is able to collect such data.”
SOFIA made its initial science flight on Nov. 30, 2010, and FORCAST principal investigator Terry Herter was on board leading the collection of data. Celestial targets imaged during the initial science flights included Comet Hartley, star-forming nebulae Messier 42, W3 IRS5, and Sharpless 140.
Image right: USRA's Jim De Buizer, at lower right, studies data with FORCAST’s principal investigator Terry Herter, left, while astronomers Eric Becklin, SOFIA Scientific Advisor, and Mark Morris from UCLA, look on during preparations for the SOFIA Observatory's initial science flight.
(NASA Photo/Tom Tschida) › View Larger Image
In 2011, researchers anticipate releasing scientific results from SOFIA’s flights, and astronomers will have the opportunity to apply for time on SOFIA in late 2011.
During 2011, the SOFIA team will start its Airborne Astronomy Ambassadors program where educators will have the opportunity to participate in science operations with SOFIA researchers. Educators will then take their experiences back to the public by presenting workshops, training other teachers, and presenting programs at schools, science centers and to groups within the local community. Additional information for educators can be found at http://www.sofia.usra.edu/Edu/edu.html
NASA’s Bob Meyer summed up the excitement SOFIA has brought to the astronomical community by saying, “Everyone on the SOFIA team has high expectations for this new phase of operations and we anticipate more valuable and intriguing scientific results will come from our next set of observations.”
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By Nicholas A. Veronico
Universities Space Research Association