1. Mauna-Kea-Observatorien (Hawaii) 2. La Palma-Observatorium (Kanarische Inseln, Spanien) 3. Mount-Wilson-Observatorium (Kalifornien, USA) 4. Paranal-Observatorium (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)