Stellar panorama revealed
Millions of images are stitched together over 4 years for epic snapshot
Millions of photos of the night sky taken from the summit of Haleakala were released to the public Monday, giving scientists one of the most complete images of the skies to date.
From 2010 to 2014, the Pan-STARRS observatory on Haleakala documented moving asteroids, glittering stars and many other objects to compile the world’s largest digital sky survey. Scientists hope the data will help lead to many discoveries.
“It’s the best snapshot of the whole sky up to this point,” Pan-STARRS astronomer Eugene Magnier said Monday. “These images will let people have sensitive, very clear, crisp images of three-fourths of the sky, all but the part that you can’t see from the summit of Haleakala.”
The Pan-STARRS 1 observatory on Haleakala is equipped with a 1.8-meter telescope and a 1.4-gigapixel camera, the largest digital camera in the world. In May 2010, astronomers began a massive survey using Pan-STARRS. One of the goals was to identify moving objects, including asteroids that could pose a threat to Earth.
“Pan-STARRS is the leading discoverer of potentially hazardous asteroids,” Magnier said. “So far at this moment, no asteroid is scheduled to hit the Earth in the known future.”
Pan-STARRS scanned the sky and took photos of each spot at various times, Magnier explained. The photos were then stacked to create a deeper image. Comparing different photographs allows scientists to see how the skies have changed over time.
“An asteroid may have moved. A supernova may have gone off,” said Dr. Ken Chambers, astronomer and director of the Pan-STARRS observatories. “We add (the photos) all together and make one deep map. You can see stuff in that final stacked image that you could never see before.”
Because Pan-STARRS uses digital technology, it produces higher resolution images than previous surveys that used photographic plates, Magnier said. The images can capture all but the southern quarter of the celestial sphere.
Using Pan-STARRS, scientists were able to map the dust in three dimensions in Earth’s galaxy. They found new streams of stars, new kinds of exploding stars and distant quasars, which are “extraordinarily bright objects” powered by material spinning into black holes, Chambers said. Quasars are like lighthouses that can help scientists discover other objects.
During the survey, scientists also discovered a “lonely planet” about seven times the mass of Jupiter, Magnier said. A lonely planet is a free-floating object that formed by itself without orbiting around a star, as most other planets do.
“It’s only by finding more examples of things like that that we can start to get more information to test our theories and models,” Magnier said.
But these discoveries barely scratch the surface, Chambers said. He compared it to an archaeological dig. Each step further out into the universe reveals “another fossil layer of things that happened in the past.”
“There’s so many new and interesting things hidden in the data,” Chambers said. “People just need to go dig in and find it. One of the motivations for this release is sort of outsourcing the science. We can’t possibly do all the science.”
The entire collection of data from 3 billion different sources, including stars and galaxies, adds up to 2 petabytes, which is equivalent to 1 billion selfies, or 100 times the content of Wikipedia. Chambers said the data could help scientists as well as students and casual users.
The Space Telescope Science Institute in Maryland and the University of Hawaii Institute for Astronomy are releasing the data in two stages. Monday’s release is the “Static Sky,” which gives the average position, brightness and colors of each object. The second, larger set of data will be released in 2017 and will provide the individual measurements and motion of each object, Magnier said.
The research program was a collaboration of 10 institutions in four countries, with support from NASA and the National Science Foundation. The team in Hawaii included 23 people — “big science by a small group of people,” Chambers said.
Not only does the immense collection of data add perspective to Earth’s place in the universe, it could also inspire the next generation of scientists, Magnier said. Magnier remembers taking his telescope to the summit of Haleakala as a kid.
“Having resources like this shows people . . . that there are exciting opportunities for kids in Hawaii,” he said. “Hawaii is a place where people do exciting science.”
The Pan-STARRS observatory is still awaiting a second telescope, expected to be operational sometime in 2017, Chambers said. Pan-STARRS 2 will have the same size telescope but a slightly better camera than Pan-STARRS 1. The debut of PS2 has been pushed back over the years. It was briefly operational in summer 2014, but since then, the Institute for Astronomy has been working to upgrade the camera and the existing dome, Chambers said. Originally, Pan-STARRS was designed to include four telescopes, but budget issues cut plans in half.
To access the Pan-STARRS survey data, visit panstarrs.stsci.edu/.
* Colleen Uechi can be reached at firstname.lastname@example.org.