Palomar Planet-Crossing Asteroid Survey

The Palomar Planet-Crossing Asteroid Survey (PCAS) was an astronomical survey, initiated by American astronomers Eleanor Helin and Eugene Shoemaker at the U.S Palomar Observatory, California, in 1973.^[2][3][4][5] The program is responsible for the discovery of 95 near-Earth Objects including 17 comets,^[6] while the Minor Planet Center directly credits PCAS with the discovery of 20 numbered minor planets during 1993–1994.^[1] PCAS ran for nearly 25 years until June 1995. It had an international extension, INAS, and was the immediate predecessor of the outstandingly successful NEAT program.^[6]

The first NEO discovered by PACS was (5496) 1973 NA, an Apollo asteroid with an exceptional orbital inclination of 68°, the most highly inclined minor planet known until 1999. In 1976, Eleanor Helin discovered 2062 Aten,^[7] the first of a new class of asteroids called the Aten asteroids with small orbits that are never far from Earth's orbit. As a result, these objects have a particularly high probability of colliding with the Earth. In 1979, Helin discovered an Apollo-type asteroid, that they later identified with the comet 4015 Wilson–Harrington.^[8] It was the first confirmation that a comet can evolve into an asteroid after it has degassed.^[6]

• Brian P. Roman
• List of minor planet discoverers § Discovering dedicated institutions
• Spacewatch
• List of near-Earth object observation projects

• Helin, E.F.; Shoemaker, E.M. (December 1979). "The Palomar planet-crossing asteroid survey, 1973–1978". Icarus. 40 (3): 321–328. Bibcode:1979Icar...40..321H. doi:10.1016/0019-1035(79)90021-6.
• Helin, E. F. (1991). "Palomar Planet-Crossing Asteroid Survey (PCAS): Recent discovery rate". Asteroids, Comets, Meteors: 235–236. Bibcode:1992acm..proc..235H.