T
| Name | Established | Location |
| Table Mountain Observatory | Angeles National Forest, Wrightwood, California, USA | |
| Tacubaya Observatory | 1882 | Tacubaya, Mexico City, Mexico |
| Taeduk Radio Astronomy Observatory | 1986 | Taejon, South Korea |
| Tamke-Allan Observatory | 1998 | Roane County, Tennessee, USA |
| Tartu Observatory | 1964 | Tartumaa, Estonia |
| Teide Observatory | 1964 | Tenerife, Canary Islands, Spain |
| Ten Acre Observatory | Tribbey, Oklahoma, USA | |
| The Heights Observatory | 1989 | The Heights School, South Australia, Australia |
| Texas A&M Astronomical Observatory | College Station, Texas, USA | |
| Theodore Jacobsen Observatory | 1895 | Seattle, Washington, USA |
| Thompson Observatory | 1968 | Beloit, Wisconsin, USA |
| Tien Shan Mountain Cosmic-Ray Station | Almaty, Kazakhstan | |
| Tuorla Observatory | 1952 | Piikkiö, Finland |
| Trieste Observatory | Trieste, Italy | |
| Turin Observatory | 1759 | Pino Torinese, Italy |
Read more about this topic: List Of Astronomical Observatories