| Zadko Observatory | Australia | Western Australia | 50 m |
| Zafaranieh Observatory | — | — | — |
 Zagreb Observatory | Croacia | — | — |
| Zaldibia observatory | España | Zaldivia | — |
| Zeds Astronomical Observatory | Pakistán | Lahore | — |
| Zeist observatory | Países Bajos | Güeldres | — |
| Zeno Observatory | Estados Unidos | Edmond | — |
| Zephyrhills observatory | Estados Unidos | Zephyrhills | — |
| Zhaoqing Magnetic Observatory | República Popular China | — | — |
 Zizzola | Italia | Bra | — |
 Zlín Observatory | República Checa | Zlín | 335 m |
| Zonalunar observatory | España | Valencia | — |
| Zuben observatory | España | Alhaurín de la Torre | — |
 Zvenigorod Observatory | Rusia | Lutsino | 184 m |
| Zvjezdarnica Graberje observatory | Croacia | Zagreb | — |
| Ähtäri Observatory | Finlandia | Ähtäri | — |
 ÇOMÜ Ulupınar Observatory | Turquía | — | 410 m |
 Épendes Observatory | Suiza | Friburgo | 680 m |
 Østervold Observatory | Dinamarca | Copenhague | — |
 Úpice observatory | República Checa | Úpice | 415 m |
 Ústecká hvězdárna | República Checa | Telnice | 480 m |
 Ďáblice Observatory | República Checa | Ďáblice | — |
 Ždánice Observatory | República Checa | Ždánice | — |
 Žebrák Observatory | República Checa | Žebrák | — |
| Žďár nad Sázavou Observatory | República Checa | Žďár nad Sázavou 3 | — |
 Ḥulwān | Egipto | Gobernación de El Cairo | 145 m |