Massive Survey Catalogues the Night Sky

Over four years, the Pan-STARRS telescope collected 2 petabytes of photos of the night sky, creating the most complete astronomical atlas yet

Night Sky
A compressed view of the entire visible sky from the Pan-STARRS1 Observatory Danny Farrow/Pan-STARRS1 Science Consortium/Max Planck Institute for Extraterrestial Physics

In May 2010, at the top of the Haleakalā Volcano on Maui, researchers from 10 institutions launched one of the most ambitious astronomy projects every conducted. Using the Panoramic Survey Telescope and Rapid Response System or Pan-STARRS telescope, they began digitally mapping the night sky. Using the 1.8-meter telescope, they scanned three quarters of the visible sky 12 times over a four year period, using five visible light and infrared filters, reports a press release.

In all, the survey imaged 3 billion astronomical objects including stars, galaxies, asteroids, gas clouds and every thing else floating in space. In total, the survey contains 2 petabytes of data, which Calla Cofield at points out is approximately 100 times the data on Wikipedia. But like Wikipedia, for the information to be useful the astronomers needed to make sure that it was properly catalogued and accessible for the researcher community. “For the past three years, we put much effort into checking the quality of the data and defining the most useful structure for the catalogue,” Dr. Roberto Saglia of the Max Planck Institute for Extraterrestrial Physics says in the press release. “In more than 100 teleconferences we discussed and improved test results, such as for astrometry or photometry for selected sky regions that have been observed previously with other telescopes. We also thought a lot about how best to combine the individual observations and how to present the relevant information for each type of objects.”

The information is being released in two batches, reports Cofield. The first, called “Static Sky” is a map of the sky averaged from Pan-STARRS 12 passes. Later in 2017, the team will release the individual images taken of each section of the sky during each of the 12 passes.

They’re not just pretty pictures. The massive sky catalogue will allow researchers to investigate galaxies, quasars, asteroids, black holes and stars like white dwarfs and brown dwarfs, reports Cofield. In fact, the researchers believe the data will allow them to create a census of all the stellar objects in our “solar neighborhood” which extends about 300 light years around the sun. It will also let researchers examine light bending around stars, which can help identify new exoplanets.

The data also shines a light outside our neighborhood, on the Milky Way itself. “Pan-STARRS1 mapped our home galaxy, the Milky Way, to a level of detail never achieved before,” Hans-Walter Rix, director of the Galaxies and Cosmology department Max Planck Institutes for Astronomy says in the press release. “The survey provides, for the first time, a deep and global view of a significant fraction of the Milky Way plane and disk—an area usually avoided by surveys given the complexity of mapping these dense and dusty regions.”

And because the telescope scanned the same bits of sky many times over a long period of time, researchers will be able to identify objects that are moving in space. In fact, the data is already leading to discoveries. In 2011, Pan-STARRS set a record by discovering 19 asteroids in one night, with a couple poised to come relatively close to earth. There have been other finds as well. “Our group discovered and studied new types of supernova explosions and the disruptions of stars by supermassive black holes from the Pan-STARRS data,” Edo Berger, an astronomer at the Harvard-Smithsonian Center for Astrophysics, a participating institution in the study, says in a statement.

A team from Taiwan also recently found a new type of luminous high-redshift quasar using Pan-STARRS. It’s expected that over the next few years, similar findings based on the sky survey will fill astronomy journals.   

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