North America Nebula
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North-America-Nebula-11-08-1997.jpg
The North America Nebula (also known as NGC 7000) is an emission nebula in the Cygnus constellation, close to Deneb (the tail of the swan and its brightest star). The remarkable shape of the emission nebula traces that of the North American continent, especially along the east coast where the Gulf of Mexico and Florida are mirrored on the sky.
General information
The North America Nebula is large, covering an area of more than ten times the size of the full moon, but its surface brightness is low so it cannot be seen with the unaided eye. Binoculars and telescopes with large fields of view (you need ~3°) will show it as a foggy patch of light under sufficiently dark skies. Its prominent shape and especially its reddish color (from the hydrogen Hα emission line) only show up in photographs of the area.
The North America Nebula and the nearby Pelican Nebula, or IC 5070, are in fact parts of the same interstellar cloud of ionized hydrogen (H II region). Between ourselves and the nebula complex lies a band of interstellar dust that absorbs the light of stars and nebulae behind it and thereby is responsible for the shape as we see it. The distance of the nebula complex is not precisely known, nor is the star that's responsible for ionizing the hydrogen so that it emits light. If it is Deneb, as some sources say, the distance would be about 1800 light years, and the absolute size of the nebula complex (6° apparent diameter on the sky) would be 100 light years.
The discovery of the North American Nebula is attributed to the famous 18th century astronomer William Herschel.
External links
- NASA APOD: The North America Nebula (May 1, 2000) (http://antwrp.gsfc.nasa.gov/apod/ap000501.html)
- NASA APOD: The North America Nebula (June 9, 1996) (http://antwrp.gsfc.nasa.gov/apod/ap960606.html)