What could be more beautiful than the starry sky? Only the starry sky, on which you can find the brightest star and distinguish the constellation from asterism. So, 10 nice and useful facts about the constellations.
Constellations are sections of the starry sky
To better navigate the starry sky, the ancient people began to distinguish groups of stars that could be linked into separate figures, similar objects, mythological characters and animals. This system allowed people to organize the night sky, making each part of it easily recognizable. This simplified the study of celestial bodies, helped to measure time, apply astronomical knowledge in agriculture and navigate the stars. The stars that we see in our sky as if in the same area, in fact, can be very far from each other. In one constellation, there may be stars that are not related to each other, both very close and very distant from the Earth.
There are 88 official constellations in total
In 1922, 88 constellations were officially recognized by the International Astronomical Union, 48 of which were described by the ancient Greek astronomer Ptolemy in his stellar catalog "Almagest" around 150 BC. There were gaps in Ptolemy's maps, especially in the southern sky. Which is quite logical - the constellations described by Ptolemy covered that part of the night sky that is visible from the south of Europe. The rest of the gaps began to be filled during the great geographical discoveries. In the XIV century, Dutch scientists Gerard Mercator, Peter Keizer and Frederic de Houtmann added new constellations to the existing list, and the Polish astronomer Jan Hevelius and French Nicolas Louis de Lacaille completed what Ptolemy had begun. On the territory of Russia, out of 88 constellations, about 54 can be observed.
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Knowledge about constellations came to us from ancient cultures
Ptolemy made a map of the starry sky, but people used the knowledge of the constellations long before that. At least in the 8th century BC, when Homer in his poems Iliad and Odyssey mentioned Bootes, Orion and Ursa Major, people were already grouping the sky into separate figures. It is believed that the main body of knowledge of the ancient Greeks about constellations came to them from the Egyptians, who, in turn, inherited them from the inhabitants of Ancient Babylon, the Sumerians or Akkads. About thirty constellations were already distinguished by the inhabitants of the Late Bronze Age, in 1650−1050. BC, judging by the records on the clay tablets of Ancient Mesopotamia. References to constellations can also be found in the Hebrew biblical texts. The most remarkable constellation, perhaps, is the constellation Orion: in almost every ancient culture it had its own name and was revered as a special one. So,in ancient Egypt he was considered the incarnation of Osiris, and in ancient Babylon he was called the "Faithful shepherd of heaven." But the most surprising discovery was made in 1972: a piece of ivory from a mammoth, more than 32 thousand years old, was found in Germany, on which the constellation Orion was carved.
We see different constellations depending on the season
During the year, different parts of the sky (and different celestial bodies, respectively) appear to our eyes, because the Earth makes its annual voyage around the Sun. The constellations that we observe at night are those located behind the Earth on our side of the Sun. during the day, behind the bright rays of the sun, we are unable to make out them.
To better understand how this works, imagine that you are riding on a carousel (this is the Earth), from the center of which a very bright, blinding light (the Sun) is emanating. You will not be able to see what is in front of you because of the light, and you can only discern what is outside the carousel. In this case, the picture will constantly change as you roll in a circle. Which constellations you observe in the sky and at what time of the year they appear depends also on the latitude of the beholder.
Constellations travel from east to west like the sun
As soon as it starts to get dark, at dusk, the first constellations appear in the eastern part of the sky to traverse the entire sky and disappear at dawn in its western part. Due to the rotation of the Earth on its axis, it seems that the constellations, like the Sun, rise and set. The constellations that we just saw on the western horizon just after sunset will soon disappear from our field of view to be replaced by constellations that were higher at sunset just a few weeks ago.
The constellations that originate in the east have a diurnal shift of about 1 degree per day: completing a 360-degree journey around the Sun in 365 days gives about the same speed. Exactly one year later, at the same time, the stars will occupy exactly the same position in the sky.
The movement of the stars is an illusion and a matter of perspective
The direction in which the stars move across the night sky is due to the rotation of the Earth on its axis and really depends on the perspective and on which side the observer is facing.
Looking north, the constellations appear to move counterclockwise, around a fixed point in the night sky, the so-called north pole of the world, located near the North Star. This perception is due to the fact that the earth rotates from west to east, that is, the earth under your feet moves to the right, and the stars, like the sun, moon and planets above your head, follow the east-west direction, that is, to the right. left. However, if you face south, the stars will move clockwise from left to right.
The zodiac constellations are those through which the sun moves
The most famous constellations of the 88 existing ones are zodiacal. These include those through which the center of the Sun passes in a year. It is generally accepted that there are 12 zodiac constellations in total, although in fact there are 13 of them: from November 30 to December 17, the Sun is in the constellation Ophiuchus, but astrologers do not rank it among the zodiacal ones. All zodiac constellations are located along the apparent annual path of the Sun among the stars, the ecliptic, at an inclination of 23.5 degrees to the equator.
Some constellations have families
are groups of constellations located in the same area of the night sky. As a rule, they assign names to the most significant constellation. The most "large" constellation is Hercules, which has as many as 19 constellations. Other large families include Ursa Major (10 constellations), Perseus (9) and Orion (9).
Celebrity Constellations
The largest constellation is Hydra, it extends over more than 3% of the night sky, while the smallest in area, the Southern Cross, occupies only 0.165% of the sky. Centaurus boasts the largest number of visible stars: 101 stars are included in the famous constellation of the southern hemisphere of the sky. The constellation Canis Major includes the brightest star in our sky, Sirius, whose brightness is −1.46m. But the constellation called Table Mountain is considered the dimmest and does not contain stars brighter than 5th magnitude. Recall that in the numerical characteristic of the brightness of celestial bodies, the lower the value, the brighter the object (the brightness of the Sun, for example, is −26.7m).
Asterism is not a constellation
Asterism is a group of stars with an established name, for example, "Big Dipper", which is included in the constellation Ursa Major, or "Orion's Belt" - three stars encircling the figure of Orion in the constellation of the same name. In other words, these are fragments of constellations that have assigned a separate name to themselves. The term itself is not strictly scientific, but rather just a tribute to tradition.
Natalya Polytsya