The Cal-Tech
Submillimeter
Observatory (CSO) is located on the summit of Mauna Kea,
Hawaii. This beautiful location allows for better observations
since the thin, dry atmosphere contains much less water vapor than
other locations around the Earth. Water vapor is a problem for
submillimeter astronomers because light in this band interacts readily
with water molecules.
The Cal-Tech Submillimeter Observatory, Mauna Kea, Hawaii
http://www.submm.caltech.edu/cso/