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Pyxis and Antlia

April 13, 2016

High technology highlights the southern evening sky at this time of year — the technology of the 18th century. A couple of small, faint constellations are named for the high-tech devices of that time.

Pyxis, the compass, is due south as night falls, just above the southern horizon. Antlia, the air pump, is to its lower left.

Nicolas Louis de la Caille created these and other technology-themed constellations in the 1750s. He journeyed to Africa to map parts of the sky that were difficult or impossible to see from Europe. He drew new constellations that covered relatively barren regions of the sky.

His constellations honored the telescope and microscope, the pendulum clock, and an early instrument for navigating at sea.

In the case of Pyxis, several of its stars once belonged to the giant constellation Argo Navis, which represented the boat that carried Jason and the Argonauts. La Caille split the constellation into thirds, with each part representing a part of the boat.

He then took a few stars that were part of the ship’s mast and turned them into Pyxis — a magnetic compass. Its brightest stars form a line that aims almost due north and south. Those stars are faint, though, so you need a clear, dark sky to see them. More about Pyxis tomorrow.

The stars of Antlia are even tougher to spot. They represent an air pump that had been invented by a French engineer a few decades earlier — a bit of high technology from the 18th century.


Script by Damond Benningfield

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