What could be more beautiful starry sky? Only a starry sky, where you can find the brightest star of the constellation and distinguish asterism. So 10 pleasant and useful facts about the constellations.
Constellations – are areas of the sky. To better navigate in the starry sky, ancient people began to allocate groups of stars, which could be attributed to the individual figures, similar objects, mythological characters and animals. This system allowed people to organize the night sky, making each portion thereof is easily recognizable. It simplified the study of celestial bodies, has helped to measure the time, apply the astronomical knowledge in agriculture and to navigate by the stars. The stars that we see in our sky as if in one area, in fact, may be very far apart. In a constellation may be unrelated to each other stars, as very close and very far from Earth.
In total there are 88 official constellations. In 1922, the International Astronomical Union was officially recognized 88 constellations, 48 of which have been described even by the ancient Greek astronomer Ptolemy in his star catalog “Almagest” about 150 BC In Ptolemy’s maps were gaps, especially in the southern sky. That is quite logical – the constellations described by Ptolemy, covered the part of the night sky that is visible from the south of Europe. The rest of the gap began to fill in the time of the great geographical discoveries. In the XIV century Dutch scientists Gerardus Mercator, Peter Keyser and Frederick de Hautman added to the existing list of new constellations, and the Polish astronomer Hevelius and French Nicolas Louis de Lacaille completed the begun by Ptolemy. On the territory of Russia and the 88 constellations can be observed around 54’s.
Knowledge about the constellations came to us from ancient cultures. Ptolemy made a map of the sky, but the knowledge of the constellations people used long before that. At least in the VIII century BC, when Homer in his poems “The Iliad” and “Odyssey” mentioned Bootes, Orion and the Big Dipper, people have grouped the sky into individual pieces. It is believed that the main body of knowledge about the constellations of the ancient Greeks came to them from the Egyptians, who, in turn inherited them from the inhabitants of ancient Babylon, Sumer and Akkad. About thirty constellations residents already allocated the Late Bronze Age, in 1650-1050 gg. BC, according to the records on clay tablets of ancient Mesopotamia. References to the constellations can be found in the Hebrew Bible texts. The most remarkable constellation, perhaps, is the constellation Orion: in virtually every ancient culture it took its name, and was regarded as a special. For example, in ancient Egypt it was considered the epitome of Osiris, and in Ancient Babylon was called “Il pastor fido heaven.” But the most surprising discovery was made in 1972 in Germany a piece of mammoth ivory has been found older than 32,000 years, which was carved the constellation of Orion.
We see different constellations depending on the time of year. During the year our eyes appear different part of the sky (and the different heavenly bodies, respectively) because the Earth makes its annual journey around the sun. The constellations that we see at night are those that are located behind the Earth on our side of the sun, because day of the bright rays of the sun, we can not see them.
To better understand how this works, imagine if you ride on the carousel (this earth), of which the center is based on a very bright, blinding light (the sun). You can not see what is in front of you because of the light, and will be able to discern just what is outside of the carousel. In this case the picture will be constantly changing as you ride around. Which constellation you see in the sky and what time of year they appear, also it depends on the latitude of the beholder.
Constellations are traveling from east to west as the sun.
As soon it begins to get dark, at dusk, in the eastern part of the sky appeared the first constellations to pass across the sky and disappear with the dawn in the western part of it. Because of Earth’s rotation around its axis creates the impression that the constellation, as well as the Sun rises and sets. Constellation, which we have just seen on the western horizon just after sunset, soon disappear from our sight, to be replaced by the constellations, which were higher than during the sunset just a few weeks ago.
Constellation arising in the east, are the daily shift of about 1 degree per day, completing 360-gradustnogo travel around the Sun in 365 days, gives approximately 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 – a matter of perspective and illusion.
The direction in which the stars move across the night sky due to the Earth’s rotation around its axis and really depends on the prospects and on which side is facing the observer.
Looking to the north, the constellations seem to move counter-clockwise, around the fixed point of 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 ground under your feet moves to the right, and the stars like the Sun, the Moon and the planets follow your head east-west, that is, on the right left. However, if you turn your face to the south, the stars will move as if clockwise, from left to right.
Zodiacal constellations are those through which the Sun moves. The most famous constellations of the 88 existing ones are the zodiacal ones. These include those through which the center of the Sun passes through the year. It is generally believed that there are only 12 zodiacal constellations, although in fact there are 13 of them: from November 30 to December 17, the Sun is in the constellation Ophiuchus, but his astrologers do not count as zodiacal. All the zodiacal constellations are located along the visible annual path of the Sun among the stars, the ecliptic, at an inclination of 23.5 degrees to the equator.
Some constellations have families – these are constellation groups located in one area of the night sky. As a rule, they assign the names of the most significant constellation. The most “large” is the constellation Hercules, which has as many as 19 constellations. Other large families include the Great Bear (10 constellations), Perseus (9) and Orion (9).
Constellations-celebrities. The largest constellation is the Hydra, it extends more than 3% of the night sky, while the smallest in the area, the Southern Cross, occupies only 0.165% of the sky. Centaurus boasts the largest number of visible stars: 101 stars enter the famous constellation of the southern hemisphere of the sky. The constellation of the Great Dog includes the brightest star of our sky, Sirius, whose brilliance is -1.46m. But the constellation with the name of Table Mountain is considered the most dim and does not contain stars brighter than the 5th magnitude. Recall, in the numerical characteristic of the brightness of celestial bodies, the smaller the value, the brighter the object (the brightness of the Sun, for example, is -26.7 m).
Asterism is not a constellation. Asterism is called a group of stars with an established name, for example, “Big Dipper”, which enters the constellation Ursa Major, or “Orion Belt” – three stars, encircling the figure of Orion in the same name constellation. In other words, these are fragments of constellations, which fixed a separate name. The term itself is not strictly scientific, but rather simply a tribute to tradition.