page_title: Asterism (astronomy)
hierarchical_section_title: Asterism (astronomy)
caption_attribution_description: Čeština: Asterismus Collinder 399 a široké okolí na amatérském snímku English: Amateur image of an asterism Collinder 399 and surroundings
context_page_description: In observational astronomy, an asterism is a popularly-known pattern or group of stars that can be seen in the night sky. This colloquial definition makes it appear quite similar to a constellation, but they differ in that: a constellation is a formally-named area of the sky and all the celestial objects within it, representing an object, person, or animal, often mythological; while an asterism is a visually obvious collection of stars and the lines used to mentally connect them. As such, asterisms do not have officially determined boundaries and are therefore a more general concept which may refer to any identified pattern of stars. This distinction between terms remains somewhat inconsistent, varying among published sources. An asterism may be understood as an informal group of stars within the area of an official or defunct former constellation, or crossing the boundaries of two or more constellations.
  Asterisms range from simple shapes of just a few stars to more complex collections of many stars, covering large portions of the sky or less than a degree.
context_section_description: In observational astronomy, an asterism is a popularly-known pattern or group of stars that can be seen in the night sky. This colloquial definition makes it appear quite similar to a constellation, but they differ in that: a constellation is a formally-named area of the sky and all the celestial objects within it, representing an object, person, or animal, often mythological; while an asterism is a visually obvious collection of stars and the lines used to mentally connect them.  As such, asterisms do not have officially determined boundaries and are therefore a more general concept which may refer to any identified pattern of stars. This distinction between terms remains somewhat inconsistent, varying among published sources. An asterism may be understood as an informal group of stars within the area of an official or defunct former constellation, or crossing the boundaries of two or more constellations.
  Asterisms range from simple shapes of just a few stars to more complex collections of many stars, covering large portions of the sky or less than a degree.  The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other.  The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. For example, the asterism known as The Plough, Charles' Wain, the Big Dipper, etc. comprises the seven brightest stars in the International Astronomical Union (IAU) recognised constellation Ursa Major. Another is the asterism of the Southern Cross, whose recognised constellation is Crux.
  Asterisms may coincide with true star clusters.  For example, the open clusters The Pleiades or Seven Sisters and  The Hyades in Taurus are sometimes referred to as asterisms, as is the much fainter NGC 2169.
caption: Collinder 399, an asterism in the constellation Vulpecula that resembles a coathanger
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