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Demoted Constellation Lives on as the Radiant of the January Quadrantids
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Quadrans Muralis: a demoted constellation lives on as the radiant of the January Quadrantids

Most meteor showers radiate from a recognizable constellation like Leo's Leonids, Gemini's Geminids and Orion's Orionids. What's up with the January Quadrantids? Where do you find their constellation? In Quadrans Muralis, a demoted constellation.

The first 60+ Roman constellations didn't cover the sky south of the equator, so over the years, astronomers took up the task and filled in the empty spaces with new constellations, including some in the northern sky.

The International Astronomical Union divided up the sky into official constellations in 1930. 88 constellations remained, but over 30 constellations didn't make the cut. Among those demoted was Quadrans Muralis, the location of January's brilliant, but brief Quadrantid meteor shower. Apis, the bee, Felis, the cat, and Solarium the sundial were other constellations demoted into obsoleteness, too. One ancient constellation, Argo Navis, didn't survive, either.

Quadrans Muralis was added to the constellations by Joseph J. de Lalande in 1795, to commemorate the quadrant he used to observe and measure stellar positions. The quadrant was an instrument very similar to today's sextant. A few years later, in the early 1800's a meteor shower was discovered to radiate from this constellation, and the meteor shower was named for the constellation.

Created from stars found to the north of Bootes, the herdsmen; Quadrans Muralis can be found in a rich area of the northern sky filled with pretty constellations. The big and little dippers (the most recognizable parts of Ursa Major and Ursa Minor) are the most familiar sights but you'll also find the Northern Crown, Corona Borealis, Bootes' two hunting dogs, Canes Venatici, and Coma Berenices, the hair of Bernice. Take a tour of the area through binoculars on January 3rd before midnight while waiting for the meteor shower. Then look between and below the big and little dippers when they are high in the wintery sky on the morning of January 4th. You should see some shooting stars in a region devoid of modern constellations, but rich in history.


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About: Jane Houston Jones
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Jane is an astronomer, NASA science podcast developer, writer, educational and outreach artisan and social media enthusiast. She and her husband have an asteroid (22338 Janemojo) named after them.
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Last Updated: 20 Jan 2011