P
| Name | Established | Location |
| Pachmarhi Array of Cerenkov Telescopes (PACT) | Pachmarhi, Madhya Pradesh, India | |
| Palisades-Dows Observatory | 1987 | Cedar Rapids, Iowa, USA |
| Palomar Observatory | 1948 | Palomar Mountain, California, USA |
| Panzano Observatory | Bologna, Italy | |
| Paranal Observatory | 1999 | Cerro Paranal, Atacama desert, Chile |
| Paris Observatory | 1667 | Paris, France |
| Parkes Observatory | 1961 | Parkes, Australia |
| Paul Robinson Observatory | 1965 | High Bridge, New Jersey, USA |
| Peach Mountain Observatory | 1950 | Dexter, Michigan, USA |
| Perkins Observatory | 1931 | Delaware, Ohio, USA |
| Perth Observatory | 1896 | Perth, Australia |
| Pic du Midi Observatory | 1878 | Pic du Midi, Pyrenees, France |
| Pico dos Dias Observatory | 1981 | Minas Gerais, Brazil |
| Piera Observatory | 1968 | Barcelona, Spain |
| Pine Bluff Observatory | 1958 | Cross Plains, Wisconsin, USA |
| Pine Mountain Observatory | 1965 | Bend, Oregon, USA |
| Pistoia Mountains Astronomical Observatory | 1990 | Pian dei Termini (near San Marcello Pistoiese), Italy |
| Portage Lake Observatory (defunct) | 1948 | Dexter, Michigan, USA |
| Poznań Observatory | 1919 | Poznań, Poland |
| Puckett Observatory | Ellijay, Georgia, USA | |
| Pulkovo Observatory | 1839 | Pulkovskiye Heights, Russia |
| Purple Mountain Observatory | 1929 | Nanjing, Jiangsu Province, China |
Read more about this topic: List Of Astronomical Observatories