At what point would the Earth's surface, we are, we always think that all the heavenly bodies are to us at the same distance on the inner surface of a sphere, which is commonly called the firmament, or just air. Day of the sky, if it is not covered with clouds, a blue color, and we see it is the brightest heavenly body - the Sun. Sometimes, in conjunction with the sun, the moon is visible during the day and very rarely, some other celestial body, such as the planet Venus. In the clear night in the dark sky, we see the stars, moon, planets, nebulae, comets, and some other body. The first impression from watching the sky - a disorder of countless stars and their location in the sky. In fact, the stars visible to the naked eye, not so much as it seems, only about 6000 the whole sky, and on one side of it, which is visible at the moment from any point of the earth's surface, no more than three thousand. The relative position of stars in the sky is changing very slowly. Without accurate measurements no significant changes in the distribution of stars in the sky can not be detected in the course of many hundreds, and for the vast number of stars - and many thousands of years. The latter circumstance makes it easy to navigate among the thousands of stars, despite the apparent randomness in their arrangement. For the purpose of orientation on the sky the bright stars have long been combined into groups called constellations. Constellations designated names of animals (the Great Bear, Lion, Dragon, etc.), the names of the heroes of Greek mythology (Cassiopeia, Andromeda, Perseus, etc.) or simply the names of those objects that resembled the shape formed by the bright stars of the group (North Crown, Triangle, Boom, Libra, etc.). In the XVII century. individual stars in each constellation are denoted by Greek letters. Somewhat later introduced a numerical numbering, currently used mostly for faint stars. In addition, the brightest stars (about 130) have their own names. For example: a Canis Major is Sirius, a Aurigae - the Chapel, a Lyrae - Vega, a Orionis - Betelgeuse, b Orion - Rigel, b Persei - Algol, etc. These names and designations of stars used in the present. However, the boundaries of the constellations outlined by ancient astronomers, and representing the sinuous lines, in 1922, have changed some of the great constellations were divided into several independent constellations, and under the constellations came to be understood not of the bright stars, and parts of the sky. Now the sky is conventionally divided into 88 separate sections - the constellations. The brightest stars in the constellations are good guidelines for finding the sky more faint stars and other celestial objects. Therefore, you must learn to quickly locate a particular constellation in the sky itself. To do this, you must first learn map the sky and remember the specific contours formed in the constellations of the brightest stars.