To capture a special celestial event, scientists turned to NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA), witnessing the moment Pluto directly passed between the Earth and a distant star.
As Pluto was backlit by the star, an occultation occurred where a faint shadow of the planet moved across the Earth's surface at over 53,000 miles per hour. This opportunity created ideal conditions for scientists to analyze a variety of things but only if observers and instruments were at the right place at the right time.
A modified Boeing 747SP jet liner, SOFIA was the only observatory with capabilities to position itself in the center of Pluto's shadow directly and over terrestrial weather. Aboard the aircraft is a telescope 8 feet in diameter, built by the German Aerospace Center, one of NASA's partners.
Operating out of New Zealand from June 15 to July 24, SOFIA makes it possible to study heavenly bodies that can only be observed, or at least more easily observed, from the Southern Hemisphere. The observatory is targeting to study 40 celestial objects, all of which can hopefully be observed within a 15-flight schedule.
The observations SOFIA made of Pluto shows that scientists have the capability to come up with detailed measurements of the planet's atmospheric structure and density, the first of which was done in July 2011, explained Pamela Marcum, program scientist for SOFIA.
"This flight adds to our understanding of how the atmosphere of Pluto evolves," she added.
To observe the celestial event, SOFIA used three instruments, all mounted on the observatory's telescope and operating simultaneously to take measurements. These include: the Hi-speed Imaging Photometer for Occultations (HIPO); the First Light Infrared TEst CAMera (FLITECAM); and the Focal Plane Imager-plus (FPI+).
One of the most notable moments captured by SOFIA during the occultation is a flash that illuminated Pluto's atmosphere at the point the star was located centered exactly behind the planet.
The occultation observed by SOFIA occurred at a unique time, happening just a couple of weeks before the New Horizons spacecraft flies its nearest to Pluto on July 14. To perform close-up studies of the system, the spacecraft will be using spectrometers, cameras and other instruments.
According to Marcum, New Horizons will provide scientists with more comprehensive measurements of Pluto. These measurements will then be combined with data gathered by SOFIA from Earth, enhancing analysis involving Pluto.
