 Daejeon Observatory | Corea del Sur | Sinseong-dong | — |
| Daito Cosmic Park Hoshi no Kuni | Japón | Gojō | — |
| Dalat Magnetic Observatory | Vietnam | — | — |
| Dan Zowada Memorial Observatory | Estados Unidos | — | — |
| Danastro Observatory | Bélgica | Doische | — |
 Daniel S. Schanck Observatory | Estados Unidos | Nuevo Brunswick | — |
| Daniel Scholl Observatory | Estados Unidos | — | — |
| Danish Telescope observatory | Chile | Ipomoea arborescens | — |
| Danzig observatory | Polonia | Gdansk | — |
| Dark Rosanne observatory | Estados Unidos | Middlefield | — |
| Dark Sky New Mexico observatory | Estados Unidos | New Mexico | — |
| Dark Sky Observatory | Estados Unidos | Carolina del Norte | — |
| Dark Sky Observatory | Estados Unidos | Carolina del Norte | — |
| Darling's Observatory | Estados Unidos | Duluth | — |
| Dataraba | — | Álava | — |
| Daventry Observatory | Reino Unido | Daventry | — |
 David Cole Observatory | Estados Unidos | Massachusetts | — |
| Deadhorse Magnetic Observatory | Estados Unidos | — | — |
 Dearborn Observatory | Estados Unidos | Evanston | 195 m |
| Debrecen Heliophysical Observatory | Hungría | — | — |
| Deep Sky observatory | Alemania | Bad Bentheim | — |
| Deep Sky Observatory Collaborative | Estados Unidos | Fort Davis | — |
| Deep Sky West Observatory | Estados Unidos | Young Place | — |
 Deep Space Climate Observatory | Estados Unidos | — | — |
| Deep Synoptic Array | Estados Unidos | condado de White Pine | — |
| Deerlick Observatory | Estados Unidos | Sharon | — |
| 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 | — |
 Dunsink Observatory | Irlanda | Dublín | — |
 Durham University Observatory | Reino Unido | ciudad de Durham | — |
| Duronia Magnetic Observatory | Italia | — | — |
| Durtal observatory | Francia | Durtal | — |
| Dushak-Erekdag Observatory | Turkmenistán | Provincia de Ahal | 2.020 m |
| Dushanbe Observatory | Tayikistán | Dusambé | — |
 Dwingeloo Radio Observatory | Países Bajos | Westerveld | — |
 Ďáblice Observatory | República Checa | Ďáblice | — |