The Planetarium Bochum explains monthly what the starry sky over Bochum has to offer. There are a few planets to discover in January.
In January, you hardly notice at first that the days are getting longer again. Nevertheless, the night between New Year’s Day and January 31 is more than an hour shorter: if the sun is 16 hours and 4 minutes below the horizon in Bochum at the beginning of the year, it is only 14 hours and 53 minutes at the end of the month.
In any case, many night hours are available for viewing the starry sky. The constellations that accompany us through an autumn night, Pegasus, Andromeda and Perseus, can still be seen well in the west and south-west in the evening. After about 10 p.m., however, they slowly begin to sink.
Just after dark, the classic constellations of winter are found in the east. In the course of time they then climb higher and higher in the sky and are already high in the south by late evening. On a clear winter night, they unfold their full splendor.
Planetarium Bochum explains: Saturn is visible for a shorter time
The most concise of the winter constellations is certainly the sky hunter Orion. His red shoulder star, Betelgeuse, and his bluish foot star, Rigel, stand out in the figure of the hunter, as do the three stars in his belt. Rigel is part of the “Winter Hexagon” formed by bright stars in six constellations.
This includes Aldebaran, a reddish giant star, the eye of the Taurus constellation. Capella, in the constellation Auriga, is the northernmost star of the hexagon. The two twin stars Castor and Pollux are almost equally bright – but Pollux, the more southern of the two, is part of the hexagon. Procyon in the Canis Minor is the only conspicuous star in this constellation and thus part of the hexagon. It is completed by Sirius in the dog major, the brightest star in the entire sky, which is only clearly visible from Bochum in winter.
Jupiter and Mars are much easier to spot
The ringed planet Saturn can only be found in the early evening before 7 p.m. At the same time, Venus begins its visibility as an evening star. In the first half of January it will be in Capricorn to the west of Saturn, not far from it, and will even set before it. Venus is moving much faster across the sky, however, passing just 0.4 degrees south of Saturn on January 22. Much brighter than Saturn, the encounter between the two planets is best observed with binoculars deep in the southwest.
At the end of January, Venus sets around 7.20 p.m. The two bright planets Jupiter in Pisces and Mars in Taurus are much easier to see. The giant planet Jupiter will be in the sky until around 11 p.m. Red Mars was near Earth in December and can still be seen for most of the night. It only disappears below the horizon around 5.30 a.m.
Highlight of the month: The Pleiades – a large “open star cluster”
The Seven Stars, also known as the Pleiades, is by far the best known and most conspicuous star cluster in the sky. It lies in the back of the constellation Taurus and is best seen on a January night. Around 9 p.m. the Pleiades are high in the south. They only say goodbye to the sky stage at 5 a.m. in the morning. This year, the bright planet Mars is also found not far from the Pleiades.
The name “Seven Stars” suggests that one sees seven stars in close proximity. However, this is usually not the case: depending on the brightness of the sky and the sharpness of your own eyes, most observers recognize five to nine stars.
In binoculars or even a telescope you can count a lot more: The Pleiades are likely to consist of more than a thousand mostly faint stars that formed together a good 100 million years ago. They form an “open star cluster” at a distance of about 440 light-years from Earth. Such a star cluster is also called “open” because its members do not stay together forever. The heap is slowly dissolving.
Bluish veils of mist surround the stars
In the case of the Pleiades, however, it will take another 250 million years before the stars that are still part of it today go their own way in the Milky Way. Longer exposure photos reveal ghostly shimmering bluish veils of mist around the Pleiades. Hidden behind are cosmic dust clouds drifting near the Pleiades, reflecting light from the cluster’s brightest stars.
The Pleiades are so conspicuous that they played a major role in the sagas of many peoples. Some researchers speculate that they were even depicted by Ice Age hunters in the Lascaux Cave more than 17,000 years ago. They are probably also depicted on the famous Nebra sky disc. There they define the beginning and end of the farming year through their position in relation to the moon. As in other cultures, they were therefore of great importance for the calendar.
Name derives from the Greek word “sailing”.
In ancient Greece, the star cluster was known as the seven nymphs, the daughters of the titan Atlas and Pleione. A story tells that the hunter Orion pursued the nymphs, after which Zeus transferred the sisters to heaven. The Orion still chases after them there, but can never reach them.
The name of the Pleiades does not come from their mythical mother Pleione, but from the Greek word “plein”, which means “sailing”. The first appearance of the Pleiades in the morning sky about 30,000 years ago marked the beginning of the season when ships could safely navigate the Mediterranean.
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