Final answer:
The best ground-based observatory sites are typically high in elevation, dark due to lack of light pollution, and dry to minimize atmospheric distortion, with prime locations including the mountains of Chile, the deserts of Arizona, the Canary Islands, and Mauna Kea in Hawaii.
Step-by-step explanation:
The best ground-based sites for astronomical observing are typically characterized as high, dark, and dry locations. The ideal characteristics of observatory sites include high altitudes, as they reduce the amount of atmosphere light needs to travel through, lessening its distortion and absorption by atmospheric gases and water vapor. Additionally, these sites are far away from urban areas to avoid light pollution, which negatively affects the ability to see faint stars and celestial objects. Some of the finest observatory locations around the world include the Andes Mountains of Chile, the Canary Islands, the deserts of Arizona, and the summit of Mauna Kea in Hawaii. Each of these places offers a unique combination of dry air, minimal light pollution, and high elevations necessary for optimizing astronomical observations.