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SUMMARY OF THE CHAPTER VI

 

Constellation is a part of the celestial sphere containing stars and other astronomical objects within precisely determined borders.

Stars in the constellations are designated by letters of Greek alphabet.

Visible brightness of stars numerically is expressed by the apparent stellar magnitude

The celestial sphere is the imagined sphere of an arbitrary radius with its center at the observer¢s eye. On the celestial sphere only angular distances are measured.

The apparent daily rotation of the celestial sphere is the result of rotation of the Earth round its axis.

The basic planes and great circles of the celestial sphere are used in the system of celestial coordinates.

In the horizontal system of coordinates the position of a star is determined by an azimuth A and star¢s altitude h.

In the equatorial system of coordinates the position of a star is determined by a declination d and a right ascensiona. Equatorial coordinates don't depend on the location of the observer. By these coordinates the stars (and other celestial bodies) are put on the celestial maps and are registered in catalogs.

MCM is used for solution of various problems such as time of rise and set, the upper and lower culminations of stars and celestial objects at different days of a year

The pattern of the star sky and picture of the daily rotation of the celestial sphere depend on the observer¢s geographic latitude.

The highest and lowest positions of a star relative to the horizon observed at its passing the celestial meridian are called the culminations of the star.

The geographic latitude of the location is equal to altitude of the celestial Pole above the horizon. Having measured the altitude of the Pole star, it is possible to determine approximately the value of the latitude.

In everyday life the zone time is used. Within each time zone the mean solar time on the central meridian is taken as the zone time.

The calendar is the system of reckoning time over extended periods. There are lunar, star, solar and lunisolar calendars.

Kepler's laws describe the main properties of motion of the planets and satellites in the Solar system: the first law determines the shape of the orbit; the second law states the nonuniformity of motion along the orbit; the third law establishes the relationship between the orbital period and the distance from the central body.

Determination of the distance to the bodies of the Solar system or to the nearby stars is based on the parallactic shift.

 


Date: 2015-01-12; view: 173


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