Looking at the night sky in childhood, we are trying to understand what constellations are. We are interested in the names formed by the stars of the figure, but not in the definition of the concept of "constellation." Meanwhile, even as adults, we do not always understand what actually lies behind this familiar word.
Projection
A spaceship flying into space will never reach any of the existing heavenly designs. The reason for this is that the stars lying, as it seems to us, on the same plane, are actually far from each other, sometimes at great distances. The constellation is a projection of a separate fragment of the celestial sphere with all cosmic objects located on it.
A bit of history
Representations of what constellations are different in different centuries. Today 88 celestial drawings are distinguished, but this was not always the case. Ancient constellations and their names were ordered and described by Ptolemy in his famous treatise "Almagest". His list included 48 celestial drawings. All of them, with the exception of one, have retained their names so far. The large constellation Argo (ship of the Argonauts) was subsequently divided into three smaller ones: Kiel, Korma and Sail. Originally, heavenly drawings, called today ancient, were described four centuries before Ptolemy, in 245 BC. e. The Greek did it too - poet Arat.
The need to supplement the existing list came at the time of the Great Discoveries: the stars marked on the maps did not help navigate the open spaces of the ocean. At the end of the 16th century, travelers Frederick de Hautman and Peter Keyser combined the stars in another 12 celestial drawings. Among them were Chameleon, Phoenix, South Hydra. A dozen constellations can still be found on the map of the southern hemisphere of the starry sky.
In 1613, Peter Planzius depicted several new celestial drawings on his globe, and in 1624, thanks to the German astronomer, physician and mathematician Jacob Barch, they began to be used throughout the scientific world. Today, only two of them are preserved on the map of the starry sky - Giraffe and Unicorn.
Final formation
The list of constellations on this has not been completed. In the 17th century, Jan Hevelius singled out seven more star drawings (Sextant, Small Lion, Lizard, Shield, Lynx, Fox, Hounds Dogs). In the next, 18th century, Nicola Louis de Lacaille also contributed. He depicted 17 constellations that completed the formation of the list.
However, the story of the names of the constellations did not end there. The ancient heavenly drawings tried several times to rename, replacing the Greek gods and heroes with Christian saints. Sometimes the glory of the Olympians wanted to feel the reigning persons and military leaders. However, all these attempts have been unsuccessful.
Borders
By the end of the 18th century, a modern understanding of what constellations are finally established. The names of heavenly images are also more or less established. It only remained to determine the boundaries.
Today, the constellation is understood not only as certain luminaries creating a recognizable silhouette. It includes the entire "territory" near these stars. The constellations are separated by borders, approved in 1935 after a long joint work of several famous astronomers.
Continuous movement
The constellations were somehow fixed on the map, but if you watch the stars all night, it is easy to notice that the celestial patterns are constantly moving. Some move around a single center, others describe an arc and hide behind the horizon. This change of position was called daily rotation. If the observer is in the Northern Hemisphere and faces south, then the stars for him will move clockwise, rising in the east and disappearing in the west. The highest constellations rise above the southern part of the horizon. If you observe the movement of stars, facing north, the picture changes somewhat. Part of the luminaries does not go beyond the horizon, but describes a circle in the sky. Its center is the so-called north pole of the world. Near it is the North Star.
In this case, the same bright point always rises and sets in a strictly defined place, unlike the Sun and the Moon, the places of sunrise and sunset of which are shifted every day. The Earth satellite and the daylight “travel” from one constellation to another. So, they “visit” twelve heavenly drawings. The sun travels its path throughout the year, and the moon - for more than 27 days. The hospitable “houses” that receive the daylight once every twelve months make up the zodiac circle.
Pillars of astrology
Perhaps everyone knows what constellations of the zodiac signs exist. It is interesting that the heavenly figure in which the Sun is located in a particular month is always hidden from the observer and appears only six months later.
Zodiac signs have been known to mankind for a very long time. Some of their names sounded back in Mesopotamia, the cradle of one of the first civilizations. The very word "zodiac" of Greek origin: zodiakos in translation means "beast". The twelve constellations received this name due to the fact that most of them are similar to animals.
The zodiac circle covers the orbit of not only the moon, but also all the planets of the solar system. It is located at an angle to the celestial equator and intersects with it at two points corresponding to the spring and autumn equinox.
The poles of the world
You can answer differently the question of what constellations are. Astronomers have developed a special coordinate system to determine them. The North Pole of the world has already been mentioned. It is easy to assume that there is also the Southern one, indicated by the constellation Southern Cross. And where the poles are, there is the equator. In the coordinate system built in the sky, there is declination (latitude, distance to the equator) and right ascension (longitude).
The equator passes through certain constellations: Orion, Pisces, Whale, Taurus, Eridanus, Sextant, Eagle, Unicorn, Hydra, Ophiuchus, Lesser Dog, Leo, Aquarius, Snake. A feature of these celestial drawings is their accessibility for observation practically anywhere in the world. This is possible precisely because of the location of the constellations.
North
There are several more classifications that complement our understanding of what constellation is. All celestial drawings are divided into those belonging to the Northern or Southern hemisphere of the starry sky.
The list of constellations of the Northern Hemisphere includes images of the three zodiac signs: Gemini, Aries and Cancer. This also includes the celestial drawings of animals: Ursa Major and Ursa Minor, Dolphin, Dragon, Giraffe, Hounds, Swan, Chanterelle, Little Horse and Little Lion, Lynx and Lizard. Among the constellations of the Northern hemisphere there are also those named after the characters of ancient mythology: Hair of Veronica, Andromeda, Cepheus, Perseus, Pegasus, Hercules, Cassiopeia, Bootes, and designating objects: Lyra, Sextant, Arrow, Triangle.
From the other side of the earth
Now let's see what constellations are visible to an observer located in the Southern Hemisphere. Most of the heavenly drawings here are named after inanimate objects and their parts: Altar, Compass, Feed, Kiel, Microscope, Bowl, Rectangle, Octant, Telescope, Pump, Cutter, Sails, Stove, Mesh, Compass, Clock, Shield, South Crown, Southern Cross and Southern Triangle. Of the zodiac signs, the southern constellations include Capricorn, Scorpio and Sagittarius. Of the mythical characters, only Phoenix and Cepheus are located here, but there are artists (Sculptor and Painter) and a representative of one of the peoples (Native American), as well as the embodiment of a miracle of nature (Table Mountain). There are many animals here: Big Dog, Raven, Dove, Wolf, Flying, Golden and Southern Fish, Crane, Hare, Bird of Paradise, Peacock, Fly, Toucan, Chameleon, South Hydra.
Winter and summer
On this, the options for answering the question of what constellation happens are not exhaustive. Another classification principle is the time of year at which the heavenly pattern is best observed. Indeed, in the summer, winter, spring and autumn, different images dominate the head.
In June, July and August, the sky is adorned with the constellations Cygnus, Lyra and Orel, the brightest points of which form the asterism Summer Triangle. At this time of year, Bootes, Northern Crown, Compasses, Hercules and several other celestial drawings are also available for observation.
In winter, the space above your head is no less beautiful than in summer. In the evening, the constellation Orion appears above the horizon. It is easy to find by three bright points lined up in a row. This is asterism Orion Belt. Below and a little to the right of it is Rigel, the most noticeable star in this heavenly figure. If the Belt continues to the left and down, then the line will soon run into Sirius, Alpha of the Great Dog and the brightest star in the whole sky. Both the Big and Small Dogs also belong to the winter constellations. From the other end, a straight line passing through the Belt of Orion abuts against Aldebaran belonging to Taurus.
Autumn and spring
The end of summer is accompanied by a change in the main constellations of the sky. Now, Pisces, Cassiopeia and Andromeda are best seen. Although their brightness is inferior to Orion and Swan, they adorn the sky no worse and are also worthy of attention.
In the spring, the space above your head is illuminated by the stars of Ursa Major, Leo, Virgo, Bootes. Of course, they are noticeable in other periods, too, but spring is the time of their “reign" in heaven.
The main constellations and names of stars have been known to us since antiquity. Since then, their list has been supplemented and modified. A list of 88 celestial drawings is an exhaustive answer to the question of what constellations are. Their names give an idea of the time of the appearance of these stellar drawings on the maps of the starry sky. So, almost all mythical characters shone in the era of Ancient Greece and Rome. Most of the animals familiar to modern man, as well as the silhouettes of artists and various devices, are the result of rethinking the star map in the 17-18th centuries. The search for constellations facilitates their relationship with the celestial equator and the poles of the world.