Editing Twilight (section)

==Astronomical twilight==
[[File:Desert Dusk.jpg|thumb|Long exposure of astronomical twilight in a small town in the [[Mojave Desert]]|left]]
[[File:Moonrise over kuala lumpur.jpg|thumb|Astronomical twilight (dusk) with a crescent moon, as seen from [[Kuala Lumpur|Kuala Lumpur, Malaysia]]]]

Astronomical twilight is defined as when the geometric center of the Sun is between 18° and 12° below the horizon.<ref name="TAPN2002" /><ref name="GOMN" /><ref name="USNO" /> During astronomical twilight, the sky is dark enough to permit astronomical observation of point sources of light such as [[star]]s, except in regions with more intense [[skyglow]] due to [[light pollution]], [[moonlight]], [[aurora]]s, and other sources of light. Some critical observations, such as of faint diffuse items such as [[nebula]]e and [[galaxy|galaxies]], may require observation beyond the limit of astronomical twilight. Theoretically, the faintest stars detectable by the naked eye (those of approximately the sixth magnitude) will become visible in the evening at astronomical dusk, and become invisible at [[Dawn#Astronomical dawn|astronomical dawn]].<ref>{{cite web |url=https://timeanddate.com/astronomy/astronomical-twilight.html |title=What Is Astronomical Twilight? |publisher=timeanddate.com}}</ref>