1. Mauna Kea Observatories (Hawaii)
2. La Palma Observatory (Canary Islands, Spain)
3. Mount Wilson Observatory (California, USA)
4. Paranal Observatory (Chile)
5. Mount Graham International Observatory (Arizona, USA)
6. Cerro Tololo Inter-American Observatory (Chile)
7. Arecibo Observatory (Puerto Rico)
8. Lowell Observatory (Arizona, USA)
9. Very Large Telescope (Chile)
10. Subaru Telescope (Hawaii)