A Mystery of Space: S T A R S- [Observatories]

Observatories are actually very large telescopes that scientists use to observe the sky in more detail than a regular telescope or the naked eye. There are many observatories located throughout the world.
Most Optical observatories (ones that a person looks through, and that use mirrors, to project the actual image) are usually located at extreme heights (on top of mountains), or at least far away from any lights that might make stars and constellations far away harder to see. Some of the largest observatories, located on Mauna Kea, which is on the Big Island of Hawaii,

The Twin Keck Observatories on Mauna Kea

are 13,796 feet (4,205 meters) high. The extremely high altitude makes the observatories stand above almost half of Earth's atmosphere, and about 90% of its water vapor. This equation equals extremely clear views of the night sky.
The Keck Observatory located on Mauna Kea is the world's largest optical telescope. The primary mirror is 387 inches (9.82 meters) wide, and is made up of 36 separate hexagonal (six-sided) segments.