Editing Ultraviolet astronomy (section)

==Overview==
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Ultraviolet [[Spectral line|line spectrum]] measurements ([[Astronomical spectroscopy|spectroscopy]]) are used to discern the chemical composition, densities, and temperatures of the [[interstellar medium]], and the temperature and composition of hot young stars. UV observations can also provide essential information about the [[Galaxy formation and evolution|evolution of galaxies]]. They can be used to discern the presence of a hot [[white dwarf]] or [[main sequence]] companion in orbit around a cooler star.<ref name=Reimers1984/><ref name=Ortiz2016/>

The ultraviolet [[universe]] looks quite different from the familiar [[star]]s and [[galaxy|galaxies]] seen in [[visible light]].
Most stars are actually relatively cool objects emitting much of their electromagnetic radiation in the visible or near-[[infrared]] part of the spectrum. Ultraviolet radiation is the signature of hotter objects, typically in the early and late stages of their [[stellar evolution|evolution]]. In the Earth's sky seen in ultraviolet light, most stars would fade in prominence. Some very young massive stars and some very old stars and galaxies, growing hotter and producing higher-energy radiation near their birth or death, would be visible. Clouds of gas and dust would block the vision in many directions along the [[Milky Way]].

Space-based solar observatories such as [[Solar Dynamics Observatory|SDO]] and [[Solar and Heliospheric Observatory|SOHO]] use ultraviolet telescopes (called [[Solar Dynamics Observatory#Atmospheric Imaging Assembly (AIA)|AIA]] and [[Extreme ultraviolet Imaging Telescope|EIT]], respectively) to view activity on the Sun and its [[solar corona|corona]]. Weather satellites such as the [[Geostationary Operational Environmental Satellite|GOES-R]] series also carry [[GOES-16#Sun-facing|telescopes]] for observing the Sun in ultraviolet.

The [[Hubble Space Telescope]] and [[Far Ultraviolet Spectroscopic Explorer|FUSE]] have been the most recent major [[space telescope]]s to view the near and far UV [[Electromagnetic spectrum|spectrum]] of the sky, though other UV instruments have flown on smaller observatories such as [[GALEX]], as well as [[sounding rockets]] and the [[Space Shuttle]].

Pioneers in ultraviolet astronomy include [[George Robert Carruthers]], [[Robert Wilson (astronomer)|Robert Wilson]], and [[Charles Stuart Bowyer]].
[[File:PIA20061 - Andromeda in High-Energy X-rays, Figure 1.jpg|thumb|center|500px|[[Andromeda Galaxy]] - in [[X-Ray astronomy|high-energy X-ray]] and ultraviolet light (released 5 January 2016).]]