Imaged on 8/13/2010
Telescope: Takahashi FSQ-106N
Camera: Canon 350Da
Exposure: 57 x 240 sec (3.8 hours) @ ISO 1600
Mount: Losmandy G11 Gemini
The
North America Nebula (
NGC 7000 or
Caldwell 20) is an
emission nebula in the
constellation Cygnus, close to
Deneb (the tail of the swan and its brightest
star). The remarkable shape of the
emission nebula resembles that of the continent of
North America, complete with a prominent
Gulf of Mexico. It is sometimes wrongly called the "North American" nebula.
The North America Nebula is large, covering an area of more than four times the size of the full
moon, but its surface brightness is low so normally it cannot be seen with the unaided eye. Binoculars and telescopes with large fields of view (approximately 3°) will show it as a foggy patch of light under sufficiently dark skies. However, using a
UHC filter which filters out some unwanted wavelengths of light, it can be seen by the naked eye under 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, (
IC 5070) are in fact parts of the same
interstellar cloud of ionized
hydrogen (
H II region). Between the Earth 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 responsible for ionizing the hydrogen so that it emits light. If the star inducing the ionization is
Deneb, as some sources say, the nebula complex would be about 1800
light years distance, and its absolute size (6° apparent diameter on the sky) would be 100 light years.
Discovered by
William Herschel on October 24, 1786 from Slough England.
-Wiki