A Mystery of Space: S T A R S- [Observatories] U12

Observatories are huge telescopes that let scientists view the sky in more detail than the naked eye allows. Observatories have telescopes that are much larger than telescopes that you can buy in a store. There are of observatories all over the world. Most optical observatories are located at great heights (on top of mountains) to get away from conditions like city lights that make observing the sky harder.

The Twin Keck Observatories on Mauna Kea

Some of the largest observatories in the world are located on the island of Hawaii. They are located 13,796 feet (4,205 meters) high on Mauna Kea. Their very high altitude puts the observatories over about half of Earth's atmosphere, and over 90% of Earth's water vapor. The height of the observatories allows very clear views of the night sky.
The largest optical observatory in the world is located on Mauna Kea. It is called the Keck Observatory. It's primary mirror is 387 inches (9.82 meters) wide, and is made of 36 separate hexagonal (six-sided) segments (parts).