ASTRONOMICAL OBSERVATORY 

  Astronomical observatory, is any structure containing telescopes and auxiliary instruments with which to observe celestial objects. Observatories can be classified on the basis of the part of the electromagnetic spectrum in which they are designed to observe.

      The largest, best developed, and most renowned of these high altitude sites is the Mauna Kea Observatory located near the summit of a 4,205 m (13,796 ft) volcano on the Island of Hawaii, which has grown to include over a dozen major telescopes during the four decades since it was founded. Several U.S. observatories offer public tours and programs, including Lowell Observatory, Kitt Peak National Observatory, McDonald Observatory,  Palomar Observatory and Griffith Observatory among others, allowing visitors to explore the cosmos and learn about astronomy.