Searching map area
National Geographic Society โ€“ Palomar Observatory Sky Survey
? TBD
astronomical survey, that took almost 2,000 photographic plates of the night sky

The National Geographic Society โ€“ Palomar Observatory Sky Survey (NGS-POSS, or just POSS, also POSS I) was a major astronomical survey, that took almost 2,000 photographic plates of the night sky. It was conducted at Palomar Observatory, California, United States, and completed by the end of 1958.

Instance of
References