Photographic Mapping

Mapping at Palomar

Creating a complete and accurate map of the Universe is one of humanity's oldest quests. Before the telescope, people used astrolabes and quadrants to map the starry dome overhead. Astronomers today use several different techniques to map the foamy network of galaxies that extends outward through space and backward through time. In the 1940s and '50s, astronomers at the Palomar Observatory used the 48-inch Schmidt Telescope to map the entire sky on photographic plates. This survey is now being repeated using high-resolution film.

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Mapping Observations

Courtesy of California Institute of Technology/STScI

Sections of the sky are recorded on three photographic plates, each sensitive to a different color. The plates are then scanned and converted to digital images like this one. The catalog compiled from the 2,682 plates will contain data on some 50 million galaxies and 2 billion stars.