Geographos and the Palomar Sky Survey

How a 1950s photographic atlas of the sky led to an asteroid named for a geography society.

Published 2026-10-23

Geographos owes its name not to geography itself but to an astronomy project.^[2]

The survey

The National Geographic Society – Palomar Observatory Sky Survey (NGS-POSS, or POSS I) took almost 2,000 photographic plates of the night sky using the 48-inch Palomar Schmidt telescope, finishing by the end of 1958.^[3] It was funded by a grant from the National Geographic Society to Caltech.^[3]

A find along the way

On 14 September 1951, Albert George Wilson and Rudolph Minkowski discovered a new asteroid at Palomar. Its observation arc actually begins two weeks before the official discovery.^[2]

The name

The asteroid was named in honour of the National Geographic Society for its support of the survey, which was headed by Minkowski, the second discoverer.^[2]

Why sky atlases matter for asteroids

Old photographic plates are a time machine. When a new asteroid is found, astronomers search archival images for earlier detections, extending the observation arc and improving the orbit. Today Geographos’ orbit is well determined for the next several hundred years.^[2]

Numbered citations link to the sources list on the Geographos overview page.