| Owls and Ravens observatory | Alemania | Holzgerlingen | — |
| P.M.P.H.R. Deep Sky Observatory | Italia | Atina | — |
| P2 Observatory | Estados Unidos | Mayhill | — |
| Pachmarhi Telescope Array | India | — | — |
| Pacific Lutheran University Keck Observatory | Estados Unidos | Parkland | — |
| Pacific Northwest Regional Observatory | Estados Unidos | — | — |
| Pacific Sky Observatory observatory | Estados Unidos | Saipan Municipality | — |
 Palanga Observatory | Lituania | Palanga | — |
| Palazzo Bindi Sergardi observatory | Italia | Siena | — |
| Palestrina observatory | Italia | Palestrina | — |
| Palisades-Dows Observatory | Estados Unidos | Iowa | — |
| Pallerols observatory | España | Pallerols | — |
| Palmer Divide Observatory | Estados Unidos | Colorado Springs | — |
| Palmerston North observatory | Nueva Zelanda | Palmerston | — |
| Palo Alto observatory | Estados Unidos | Palo Alto | — |
| Palomar Mountain-DSS | Estados Unidos | Palomar Mountain | — |
| Palominas Observatory | Estados Unidos | Sierra Vista Southeast | — |
| Pamatai Magnetic Observatory | Francia | Polinesia Francesa | — |
| Pampilhosa da Serra Observatory | Portugal | — | — |
 Pan-STARRS | Estados Unidos | Maui County | — |
| Panagjurishte Magnetic Observatory | Bulgaria | Pazardzhik | 556 m |
| Panameno observatory | Chile | San Pedro de Atacama | — |
 Pandora | Estados Unidos | — | — |
| Panker observatory | Alemania | Panker | — |
 Panská Ves observatory | República Checa | Dubá | — |
| Panzano Observatory | Italia | Castelfranco Emilia | — |
| PAO observatory | Italia | Prato | — |
| Para Todos Remote Observatory | España | — | — |
| Paratunka Magnetic Observatory | Rusia | — | — |
 Parc Astronòmic Montsec | España | Ager | — |
 Pardubice observatory | República Checa | Pardubice | 230 m |
| Parma observatory | Italia | Parma | — |
| Partizanske observatory | Eslovaquia | Trenčín | — |
| PASTIS Observatory | Francia | Banon | — |
 Paul Robinson Observatory | Estados Unidos | Municipio de Lebanon | — |
 Paul Wild Observatory | Australia | New South Wales | — |
| Paus observatory | España | Sabadell | — |
 Peach Mountain Observatory | Estados Unidos | Míchigan | — |
| Pear Tree observatory | Estados Unidos | Valparaiso | — |
| Penn Heights Observatory | Reino Unido | Rickmansworth | — |
| Penrith Observatory | Australia | New South Wales | 60 m |
| Penteli Magnetic Observatory | Grecia | Dionisos Municipality | — |
 Penteli Observatory | Grecia | municipio de Penteli | — |
| Penwortham observatory | Australia | Penwortham | — |
| Penzing Astrometric observatory | Austria | Viena | — |
| Perak Observatory | Malasia | Manjung | — |
| Perkins Observatory | Estados Unidos | Delaware | — |
| Perpignan observatory | Francia | Perpiñán | — |