Editing Observational astronomy (section)

{{short description|Division of astronomy}}
[[File:Mayall Telescope.jpg|thumb|250px|[[Nicholas U. Mayall Telescope|Mayall telescope]] at [[Kitt Peak National Observatory]]]]
[[File:Astronoomiahuvilised.jpg|right|thumb|250px|An assembly in [[Estonia]] to observe [[Perseids|meteors]]]]

'''Observational astronomy''' is a division of [[astronomy]] that is concerned with recording [[data]] about the [[observable universe]], in contrast with [[theoretical astronomy]], which is mainly concerned with calculating the measurable implications of [[physical model]]s. It is the practice and study of [[observation|observing]] [[celestial object]]s with the use of [[telescope]]s and other astronomical instruments.

As a [[space science|science]], the study of astronomy is somewhat hindered in that direct [[experiment]]s with the properties of the distant [[universe]] are not possible. However, this is partly compensated by the fact that astronomers have a vast number of visible examples of stellar phenomena that can be examined. This allows for observational data to be plotted on graphs, and general trends recorded. Nearby examples of specific phenomena, such as [[variable star]]s, can then be used to infer the behavior of more distant representatives. Those distant yardsticks can then be employed to measure other phenomena in that neighborhood, including the distance to a [[galaxy]].

[[Galileo Galilei]] turned a [[telescope]] to the heavens and recorded what he saw. Since that time, observational astronomy has made steady advances with each improvement in telescope technology.