Constellations for February 2023 – Orion and Lepus
Orion is one of the few constellations that is both easily recognised and like the figure it is meant to represent. It is easily spotted to the south on winter evenings with its seven bright stars. Under Orion is another ancient constellation, Lepus, the Hare, which looks like a hare with two ears, but being so low down is not so easy to make out. Diagonally opposite each other, and almost equally bright, Betelgeuse (often pronounced “beetlejuice”) is a red supergiant while Rigel is a rare blue supergiant, although to the naked eye they look orange and white. Three years ago, at the beginning of 2020, Betelgeuse dimmed quite dramatically for about three months, probably caused by huge clouds of soot on its surface. Most of Orion is connected and is about 1,300 light years away in a neighbouring arm of the Milky Way.
The most prominent features of Orion are its belt of three closely spaced stars and hanging down from the belt, the sword which contains that most wonderful of sights, the Orion Nebula [1] which is also called Messier 42. Visible to the naked eye, even in Havering, it is even more splendid in binoculars or a telescope. It is a giant cloud of gas and dust in which new stars are being formed.
Eventually hot winds from the young stars will blow this dust away, and the Orion Nebula will become a star cluster like the Pleiades. If you use a telescope, you should be able to make out four tiny stars close together, which is called the Trapezium. Just below the bottom star of the “sword” (which is called Hatysa or Nair-al-Saif, which means “the bright one of the sword”) you can make out the double star Struve 747 [2], which has two bright white stars widely apart, surrounded by nebulosity. Hatysa itself is a double star which is more difficult to split.
The right-hand star of the belt,
Mintaka
is another wide double star, which consists of a white star and a much dimmer blue star. Above the left-hand star, Alnitak, in the direction of Betelgeuse is
Messier 78 [3]. It is easy to find, but in a small telescope it looks like two fairly bright but small blobs, like a cosmic colon sign.
Just below Alnitak is
Sigma Orionis which is a complex multiple system. The main star and the two brightest secondaries are more or less white and form a fishhook shape. At the top of Orion, is
Meissa; a triple star, with two bright stars very close together and a much dimmer one below the close pair but much further away. There are many other stars in this region and Meissa is part of a large star cluster called Collinder 69 (and Orion’s belt is Collinder 70). Another interesting Collinder cluster is Collinder 83 (NGC 2169) above Orion which is also called the 37 Cluster [4] [pictured left], as it looks remarkably like the number 37. 3,600 light years away, it is a cluster of hot young OB stars. The Collinder catalogue of star clusters was published by the Swedish astronomer Per Collinder (1890-1975) in 1931. He was also a historian of astronomy and navigation. The best-known Collinder cluster, Collinder 399 (Brocchi’s Cluster or Coathanger) is in fact an asterism, not a cluster.
Lepus is another ancient constellation and represents a hare being chased by Orion’s two dogs. It contains the famous red star, Hind’s Crimson Star [5] (R Leporis), which was found by John Russell Hind (1823-1895) in 1845 and Gamma Leporis, a widely spaced double with a yellow star and a dimmer blue star. Lepus also has Messier 79 [6], a globular cluster below Nihal and almost level with Epsilon Leporis. However it is both faint and low in the sky (never more than 13 degrees high), thus making it very difficult to observe at our latitude.
