Although geological and meteorological observatories exist, the term is generally applied to astronomical observatories. The function of the astronomical observatory is centered around the telescope . In addition to visual and photographic observations of astronomical bodies and phenomena, perhaps the most valuable use of the telescope is in connection with the spectroscopic study of starlight. The temperature and chemical composition of stars can be obtained by this method, as well as information about stellar motion and magnetic fields. Using computers, astronomers can measure the spectra digitally recorded by spectrographs and photometers.
Observatories specializing in solar astronomy usually have coronographs and spectroheliographs.
Atmospheric limitations on telescopic observations include weather conditions, air turbulence, air glow, pollution, and any source of extraneous illumination. To minimize such conditions optical observatories are generally located at high altitudes in sparsely populated areas. See articles on specific observatories. Development of the Astronomical Observatory Early civilizations, such as those of Babylon, China, and Egypt, recognized the regular and periodic nature of heavenly motions and established primitive observatories to maintain astronomical records. The main purposes of these early observatories were to regulate the calendar and predict the changes of season.