Many of the leading surveys now coming online are based in the southern hemisphere, where celestial cartographers can expect to make the greatest impact. In the north, the granddaddy of all astronomical surveys—the Sloan Digital Sky Survey in New Mexico—has reigned for more than a decade and has already carefully mapped more than one million galaxies in three dimensions, in addition to many other accomplishments.
Among the new crop of southern surveys is a project at the European Southern Observatory’s VISTA telescope in Chile, which is already carrying out a broad infrared survey to complement the more targeted Dark Energy Survey. And the SkyMapper project in Australia plans to chart the entire southern sky in optical light. The SkyMapper telescope should detect roughly one billion stars and one billion galaxies, according to Stefan Keller of the Australian National University, one of the project’s lead scientists.
But the telescope most likely to rewrite the books on the southern sky is the Large Synoptic Survey Telescope, or LSST, in Chile. When it comes online around 2022, the LSST—as currently envisioned—will feature an 8.4-meter mirror (compared to the Sloan survey’s 2.5-meter telescope) and a three-gigapixel digital camera. The mammoth telescope will image the heavens every week to capture transient phenomena such as supernovae and close passages of potentially dangerous asteroids. In the process, it will also mark the three-dimensional location of some four billion galaxies.