The constellation Pyxis

Characteristics

Other names / Symbolism

Compass

Hemisphere

Southern hemisphere

Visibility

January - March

Area

221 deg²

Brightest star

α Pyxidis (HIP number 42828)

Specialties

Open star clusters, planetary nebula, galaxy

The Pyxis, known as Compass, is a small and inconspicuous constellation in the southern sky. It was introduced by the French astronomer Nicolas Louis de Lacaille in the mid-18th century. There are only a few deep-sky objects located in this area.

Hemisphere, visibility, and area

The constellation Pyxis lies in the southern hemisphere and is visible from many places. While it is fully visible in the night sky for all regions south of the equator, it can be observed up to the 53rd parallel in the northern hemisphere. This corresponds to places such as Hamburg in Germany or Edmonton in Canada.

The months of January to March offer the best conditions for observing the constellation. It stretches over about 221 square degrees in the night sky and is ranked 65th in terms of size compared to all other 88 constellations.

However, finding the Pyxis is not easy, as there are only faint stars in its area. In most visualizations, the three main stars are connected in a straight line. The brightest star is α Pyxidis (Alpha Pyxidis), with an apparent magnitude of only 3.68. It is located about 1,200 light-years away.

To still discover the Pyxis, it is helpful to orient oneself to the surrounding constellations. To the north lies Hydra, and to the east is Vela. Southern Puppis is located, and to the west Antlia is situated.

Specialties in the constellation

In the constellation area lies the Milky Way band, which provides for open star clusters, a galaxy and a planetary nebula.

The planetary nebula NGC 2818 is the brightest object, with an apparent magnitude of roughly 8.2. It was discovered by the Scottish astronomer James Dunlop in May 1826.

The open star cluster with the catalog number NGC 2627 is only slightly fainter. It has an apparent magnitude of about 8.4. It was found by the German-British astronomer William Herschel in March 1793.

Just a few years earlier, he also discovered the spiral galaxy NGC 2613. It has an apparent magnitude of approximately 10.4, and its distance from the Milky Way is estimated to be about 66 million light years.

History

The French astronomer Nicolas Louis de Lacaille measured the positions of over 10,000 stars between 1750 and 1754 and subsequently defined several new constellations, including the Pyxis, often just called Compass.

During his sky survey conducted near Cape Town in South Africa, he found that the ancient constellation Argo Navis was too large and unwieldy. Therefore, he divided it into the three constellations of Carina (the keel), Vela (the sails), and Puppis (the stern). In doing so, he discovered the stars of the Pyxis and classified them accordingly.

In the 19th century, the son of German-British astronomer William Herschel proposed renaming the constellation as the mast of the ship to honor the ancient constellation of Argo Navis, but this suggestion was never adopted.