| Hibiscus observatory | Francia | Puna'auia observatory | — |
| Hida Observatory | Japón | Takayama | — |
| Hidaka Observatory | Japón | Hidaka | — |
| Hidden Valley Observatory | Estados Unidos | Dakota del Sur | — |
| Higashi-Hiroshima Observatory | Japón | Higashihiroshima | — |
 Higginson Tower | Canadá | Champlain | — |
| High Altitude Observatory | Estados Unidos | South Kona | — |
| High Point observatory | Estados Unidos | High Point | — |
| High Resolution Fly's Eye Cosmic Ray Detector | Estados Unidos | Utah | — |
 High School, Academy Road, Stirling | Reino Unido | Stirling | — |
| Highland Road Park Observatory | Estados Unidos | Luisiana | — |
| Highworth observatory | Reino Unido | Highworth | — |
| Hilbre Bird Observatory | Reino Unido | — | — |
| Hill Town Local Studies Museum “Miku” | Japón | Prefectura de Hokkaido | — |
| HillTopTop observatory | Estados Unidos | Edgewood | — |
| Himalayan Chandra Telescope, IAO | India | Eugen Hänle | — |
| Hin Hua Observatory | Malasia | — | — |
 Hinode | — | — | — |
| HIPAS Observatory | Estados Unidos | Alaska | — |
 Hipparcos | — | — | — |
| Hirao Observatory | Japón | Hirao | — |
| Hiratsuka observatory | Japón | Hiratsuka | — |
 Hirsch Observatory | Estados Unidos | — | — |
 Hisaki | — | — | — |
 Hitomi | — | — | — |
| HOB Observatory | Italia | Capraia | — |
 Hohenpeißenberg Meteorological Observatory | Alemania | Hohenpeißenberg | — |
 Hoher List Observatory | Alemania | Daun | 504 m |
 Holcomb Observatory and Planetarium | Estados Unidos | Indiana | — |
 Holden Observatory | Estados Unidos | Siracusa | — |
| Holme Bird Observatory | Reino Unido | Norfolk | — |
| Holomon Observatory | Grecia | — | — |
| Homburg-Erbach observatory | Alemania | Erbach | — |
 Hondelage observatory | Alemania | Brunswick | — |
| Honjo observatory | Japón | Honjō | — |
 Honolulu Magnetic Observatory | Estados Unidos | Ewa Beach | 4 m |
 Hoober Observatory | Reino Unido | Yorkshire del Sur | — |
| Hoogeveen observatory | Países Bajos | — | — |
| Hope Observatory | Estados Unidos | Maryland | — |
 Hopkins Ultraviolet Telescope | — | — | — |
| Horizon observatory | Kazajistán | Petropavl | — |
| Hormersdorf Observatory | Alemania | Hormersdorf | — |
| Hornsby Bend Bird Observatory | Estados Unidos | Texas | — |
| Hornsund Magnetic Observatory | Noruega | Svalbard | — |
| Horus observatory | España | Cártama | — |
 Hoshi no Mura Observatory | Japón | Tamura | — |
| Hottviller observatoire | Francia | Hottviller | — |
| Houston observatory | Estados Unidos | Houston | — |