| Western Great Lakes Bird and Bat Obs'tory | — | — | — |
 Westfälische Volkssternwarte | Alemania | Westviertel | 110 m |
 Weston Observatory | Estados Unidos | Nuevo Hampshire | — |
 Weston Observatory | Estados Unidos | Weston | — |
 Westport Observatory | Estados Unidos | Westport | — |
| WestRock Observatory | Estados Unidos | Columbus | — |
| Westwood observatory | Estados Unidos | Westwood | — |
 Wettzell 20m radio telescope | Alemania | — | — |
| Weybourne Atmospheric Observatory | Reino Unido | Weybourne | — |
| Whakatane Astronomical Society | Nueva Zelanda | Whakatāne District | — |
| Whangarei Observatory | Nueva Zelanda | — | — |
| Whipple observatory | Estados Unidos | Cañón de Madera | — |
| Whipple Observatory | Estados Unidos | Madera Canyon | — |
| Whiskey Creek Observatory | Estados Unidos | Silver City | — |
 Whitefish Point Bird Observatory | Estados Unidos | Míchigan | — |
| Whitestar observatory | Italia | Tricesimo | — |
 Whitin Observatory | Estados Unidos | Massachusetts | — |
| WHOO! | República Checa | Opava-Předměstí | — |
| Wickede observatory | Alemania | Dortmund | — |
 Wide Field Infrared Explorer | Estados Unidos | — | — |
 Wide-field Infrared Survey Explorer | Estados Unidos | — | — |
| Widener University Observatory | Estados Unidos | Pensilvania | — |
| Wiechert’sche Erdbebenwarte | Alemania | Gotinga | — |
| Wiesbaden Observatory | Alemania | Wiesbaden | 190 m |
 Wigglesworth Observatory | Reino Unido | — | — |
| Wildberg observatory | Alemania | Wildberg | — |
 Wilder Observatory | Estados Unidos | Massachusetts | — |
| Wilfred Hall Observatory | Reino Unido | Ciudad de Preston | — |
 Wilhelm-Foerster-Sternwarte (Berlin, Germany) | Alemania | Tempelhof-Schöneberg | 78,4 m |
| Willard L. Eccles Observatory | Estados Unidos | Utah | — |
| William Miller Sperry Observatory | Estados Unidos | Nueva Jersey | — |
| Williams Observatory | Estados Unidos | Carolina del Norte | — |
| Willow Bank Observatory | Reino Unido | Todmorden | — |
| Willowed Plains Observatory | Estados Unidos | Manteno | — |
| Wimborne Minster observatory | Reino Unido | Wimborne Minster | — |
| Winchester observatory | Estados Unidos | Winchester | — |
| Windsor observatory | Australia | — | — |
| Winer Observatory | Estados Unidos | Sonoita | — |
| Winfree Observatory | Estados Unidos | Lynchburg | — |
| Wingst Magnetic Observatory | Alemania | Wingst | 50 m |
| Wishing Star Observatory | Estados Unidos | Barrington | — |
| Wither observatory | Nueva Zelanda | Witherlea | — |
 WMAP | — | — | — |
| Wobblesock observatory | Australia | Coonabarabran | — |
| Woogaroo Observatory | Australia | Forest Lake | — |
| Woolston Observatory | Reino Unido | North Cadbury | — |
| Wormout observatory | Francia | Wormhout | — |
| Wyncroft observatory | Reino Unido | Attleborough | — |