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One of the best-known of the abandoned constellations, because it has given its name to the annual meteor shower known as the Quadrantids that radiates from this area every January. Quadrans Muralis occupied what is now the northern part of Boötes, near the end of the Plough’s handle (or, alternatively, the tip of the Great Bear’s tail).

The constellation was invented by the French astronomer Joseph Jérôme de Lalande to commemorate the wall-mounted quadrant that he and his nephew Michel Lefrançois de Lalande (1766–1839) used for measuring star positions (“muralis” is Latin for “wall”). Lalande took his cue from his countryman Nicolas Louis de Lacaille who, forty years earlier, had populated the southern sky with new constellations representing scientific instruments. Lalande followed suit by putting a quadrant in the northern sky.

Quadrans Muralis first made its appearance under the name Le Mural in the 1795 edition of the Atlas Céleste of Jean Fortin, another Frenchman; this revised edition was edited by Lalande and his colleague Pierre Méchain. The new constellation appeared on only one plate of the atlas (Plate 2) and was not mentioned in the accompanying star tables, which remained unchanged from the first printing. However, in a table of circumpolar stars published in 1796 in the Connaissance des Temps, Lalande listed ten stars of 5th to 7th magnitude as belonging to the constellation, although more than this were shown on the atlas.

Its name was Latinized from Le Mural to Quadrans Muralis by Bode in 1801 on his Uranographia star atlas. Bode shrank the constellation slightly by comparison with Lalande’s original to avoid overlap with its established neighbours. However, despite Bode’s endorsement it was never widely adopted.

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Quadrans Muralis lay just above the outstretched arm of Boötes, with the body of Draco further north. It is depicted here on the Uranographia of Johann Bode (1801).



© Ian Ridpath. All rights reserved


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