Later named Supernova 1987A, this exploded star marked the first known supernova visible to the naked eye since 1604. From thousands of observatories throughout the world, such astronomical phenomena are continually monitored, measured, and analyzed. Astronomical observatories, aimed at objects located a great distance from the Earth, are the most common type of observatories. Other observatories, called meteorological observatories, examine the weather.
Geophysical observatories research the movements of the Earth's crust.
This article will focus on astronomical observatories. The purpose of an astronomical observatory is to gather information that will lead to an understanding of the nature of the universe and its various components. Among the many celestial bodies examined by astronomical observatories are planets, stars, comets, galaxies, quasars, and nebulas. Even the simplest observatories can provide a detailed look at stars whose light has traveled for thousands of years before reaching the Earth. The largest and most sophisticated observatories routinely study objects from which light has traveled for 10 billion years or more.