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Lyra (Constellation): Difference between revisions
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Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months. | Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months. | ||
[[Messier 57]] also known as the "Ring Nebula" and NGC 6720, has a diameter of one light-year and is at a distance of 2,000 light-years from Earth. It is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8. It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula. Astronomers have determined that it is between 6,000 and 8,000 years old; it is approximately one light-year in diameter.The outer part of the nebula appears red in photographs because of emission from ionized hydrogen. The middle region is colored green; doubly-ionized oxygen emits greenish-blue light. <ref>[http://en.wikipedia.org/wiki/Lyra Lyra]]</ref> | [[Messier 57]] also known as the "Ring Nebula" and NGC 6720, has a diameter of one light-year and is at a distance of 2,000 light-years from Earth. It is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8. It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula. Astronomers have determined that it is between 6,000 and 8,000 years old; it is approximately one light-year in diameter.The outer part of the nebula appears red in photographs because of emission from ionized hydrogen. The middle region is colored green; doubly-ionized oxygen emits greenish-blue light.<ref>[http://en.wikipedia.org/wiki/Lyra Lyra]]</ref> | ||
In the past, Lyra was often represented on star maps as a vulture or an eagle carrying a lyre, either enclosed in its wings, or in its beak. It was sometimes referred to as Aquila Cadens or Vultur Cadens (falling eagle or falling vulture).This historical association is preserved in the name of its brightest star, [[Vega]], which is derived from an Arabic term meaning "swooping eagle". | |||