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}} {{arXiv|1711.02174}}

}} {{arXiv|1711.02174}}

</ref> The nebula is around 110&nbsp;ly across, corresponding to an apparent size of 3 degrees.<ref>{{cite web|url=https://apod.nasa.gov/apod/ap191031.html|title=The Ghostly Veil Nebula|accessdate=2019-12-23|publisher=apod.nasa.gov|date=2019-10-31}}</ref> It covers an area of the night sky equal to around six full [[Moon]]s. The debris in the nebula is moving rapidly at roughly 600,000 kilometres per hour.<ref name=constellation-guide/> This results in shock fronts forming that heat the gas in the nebula to millions of [[kelvin]]. The material then glows as it cools. Although bright, the large area results in a low surface brightness and an OIII filter is recommended for observations.<ref>{{cite web|url=http://spider.seds.org/spider/Misc/veil.html|title=NGC 6960, 6979, 6992, 6995: The Veil Nebula|accessdate=2019-12-23|publisher=spider.seds.org}}</ref> The brightness of the nebula varies across the nebula due to variations in the [[density]] of the gas present in the nebula, with denser regions being brighter.<ref>{{cite web|url=https://www.skyandtelescope.com/astronomy-blogs/explore-night-bob-king/explore-veil-nebula/|title=Explore the Veil Nebula|accessdate=2019-12-23|publisher=skyandtelescope.com|date=2018-09-15|author=Bob King}}</ref>

</ref> The nebula is around 110&nbsp;ly across, corresponding to an apparent size of 3 degrees.<ref>{{cite web|url=https://apod.nasa.gov/apod/ap191031.html|title=The Ghostly Veil Nebula|accessdate=2019-12-23|publisher=apod.nasa.gov|date=2019-10-31}}</ref> It covers an area of the night sky equal to around six full [[Moon]]s. The debris in the nebula is moving rapidly at roughly 600,000 kilometres per hour.<ref name=constellation-guide/> This results in shock fronts forming that heat the gas in the nebula to millions of [[kelvin]]. The material then glows as it cools. Although bright, the large area results in a low surface brightness and an OIII filter is recommended for observations.<ref>{{cite web|url=http://spider.seds.org/spider/Misc/veil.html|title=NGC 6960, 6979, 6992, 6995: The Veil Nebula|accessdate=2019-12-23|publisher=spider.seds.org}}</ref> The brightness of the nebula varies across the nebula due to variations in the [[density]] of the gas present in the nebula, with denser regions being brighter.<ref name=skyandtelescope>{{cite web|url=https://www.skyandtelescope.com/astronomy-blogs/explore-night-bob-king/explore-veil-nebula/|title=Explore the Veil Nebula|accessdate=2019-12-23|publisher=skyandtelescope.com|date=2018-09-15|author=Bob King}}</ref>

Observations of the nebula in non-optical regions of the [[electromagnetic spectrum]] have revealed many interesting facts about the nebula. The nebula is a source of [[radio]] emissions and possess the designations W87 and Shapeless&nbsp;101 for this.<ref>{{cite web|url=https://www.britannica.com/place/Cygnus-Loop|title=Cygnis Loop|accessdate=2019-12-23|publisher=britannica.com}}</ref> It is also one of the largest and brightest sources of [[x-ray]]s in the night sky.<ref>

Observations of the nebula in non-optical regions of the [[electromagnetic spectrum]] have revealed many interesting facts about the nebula. The nebula is a source of [[radio]] emissions and possess the designations W87 and Shapeless&nbsp;101 for this.<ref>{{cite web|url=https://www.britannica.com/place/Cygnus-Loop|title=Cygnis Loop|accessdate=2019-12-23|publisher=britannica.com}}</ref> It is also one of the largest and brightest sources of [[x-ray]]s in the night sky.<ref>