| DeKalb Observatory | Estados Unidos | Auburn | — |
| Del Celado observatory | Italia | — | — |
| Del Rio Magnetic Observatory | Estados Unidos | — | — |
| Deokheung Optical Astronomy Observatory | Corea del Sur | Goheung County | — |
| Dertingen observatory | Alemania | Dertingen | — |
| Desert Beaver Observatory | Estados Unidos | Arizona | 261 m |
| Desert Moon Observatory | Estados Unidos | Las Cruces | — |
| Desert Wanderer observatory | Estados Unidos | Imperial County | — |
| DeSS Deimos Sky Survey observatory | España | El Horcajo | — |
| Detmold observatory | Alemania | Detmold | — |
| Dettelbach Vineyard Observatory | Alemania | Dettelbach | — |
| Dettenhausen observatory | Alemania | Dettenhausen | — |
 Devasthal Observatory | India | Nainital | 2.450 m |
| Diadema Municipal Astronomical Observatory | Brasil | São Paulo | — |
| DiezALaOnce observatory | España | provincia de Guadalajara | — |
| Digital Stargate observatory | Italia | Manciano | — |
| Digitized Sky Survey | Australia | New South Wales | — |
| Dilbert observatory | Estados Unidos | Forest Grove | — |
| Dingle Observatory | Gales | Montgomery | — |
| Discovery Observatory | Brasil | Caruaru | — |
| Divine Creation Observatory | Estados Unidos | Fort Davis | — |
| Doc Greiner Research observatory | Estados Unidos | Evansville | — |
| Dogsheaven Observatory | Brasil | Núcleo Bandeirante | — |
| Dolomites observatory | Italia | Provincia autónoma de Trento | — |
| Dome C Magnetic Observatory | — | — | — |
 Dominion Observatory | Nueva Zelanda | Región de Wellington | — |
 Dominion Radio Astrophysical Observatory | Canadá | Columbia Británica | 546 m |
| Don Astronomical Observatory | Rusia | Rostov del Don | — |
 Dora Observatory | Corea del Sur | Gyeonggi | — |
| Dordrecht observatory | Países Bajos | Dordrecht | — |
| Dourbes Magnetic Observatory | Bélgica | — | — |
| Doyan Rose Observatory | Estados Unidos | Indianápolis | — |
 Dr. A.F. Philips Observatory | Países Bajos | Eindhoven | — |
 Dr. Neil Trivett Global Atmosphere Watch Observatory | Canadá | Nunavut | — |
 Dr.-Remeis-Sternwarte | Alemania | Bamberg | — |
| Drake Municipal Observatory | Estados Unidos | Iowa | — |
| Drake University observatory | Estados Unidos | Des Moines | — |
| DreamSky Observatory | Ucrania | Khodosivka | — |
 Drebach Observatory | Alemania | Drebach | 492 m |
| Drebach-South Observatory | Namibia | Khomas Region | — |
| Dridri Observatory | Italia | Dosso | — |
| Driesen observatory | Polonia | Drezdenko | — |
| Drum Hill Station | Estados Unidos | Chelmsford | — |
 DSS 14 | Estados Unidos | California | — |
| Dumont d'Urville Magnetic Observatory | — | — | — |
| Dun Echt Observatory | Reino Unido | Westhill | — |
| Dunboyne Castle Observatory | Irlanda | af Chapman | — |
| Dungeness Bird Observatory | Reino Unido | Kent | — |