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The (Mariner’s) Compass

Constellation of the southern sky

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Map of Pyxis Map of Pyxis


Relative Galactic Position of Pyxis

The stars of Pyxis fall within a slice of sky that lies within the disc of our home Galaxy, and so appear within the band of the Milky Way in the night sky.

Pyxis was introduced by Abbé de la Caille, and associated with the giant 'superconstellation' of Argo Navis. In naming the constellation, though, de la Caille encountered a problem: there is no Latin word for 'compass', because the Romans did not have them. To solve this, he chose the word pyxis, which literally means 'little box'. The full name of the constellation, not now used, was Pyxis Nautica, meaning 'The Mariner's Box' or 'The Mariner's Compass'.


Though it lies on the plane of the Milky Way, there are few bright stars in this constellation. The brightest is Alpha Pyxidis or Al Sumut, with a magnitude of just +3.7. It lies more than 800 light years away, but it is a highly luminous body and hence visible from Earth. The other stars of the constellation are a little closer, but all are fainter than magnitude +4.0.

Only one of the stars of Pyxis lies anywhere close to the Earth's solar system: HR 3430 is a binary star, consisting of a pair of yellow dwarf stars, that lies 65 light years from the Sun.


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