What is Efmeris?
efemeris is a table that provides information on the positions of heavenly objects such as stars and planets in given data in the past or in the future. It can also display positions of satellites created by man. The term whose plural is ephemerides comes from the Greek word for a diary or diary. Since ancient times, man has portrayed the positions of stars and planets in the sky, for various reasons for religion, navigation and recently space travel. It seems that cave painting found in Lascaux, of which about 15,000 BCE depicts the phases of the moon and can be considered the first known monthly ephemeris, but it seems that the oldest known planetary ephemerides were produced by Babylonians around 523 BCE.
It seems that in the early times ephemerides were used to predict the solar eclipse and in some cultures they tried to predict the future. Often it was a henievel that the position of planets in the sky,Due to the constellations and to each other, they were important for matters on Earth: certain configurations were considered favorable and others did not. It was assumed that the configuration of planets at the time of birth affects the character and fate of this person, and the ephemerides were used to try to predict what lies for people and for society in general. In this way, they are still used by astrologers; However, there are differences between astrological ephemeris and astronomical ephemeris. Astrological ephememeides usually provide planetary positions on ecliptic with respect to folk equinoxes and show the zodiacal constellation in which the planet is located in the date.
The main items of astronomical data Efemeris for the planet and the date are the correct rise and decline. They can be considered essentially horizontal and vertical position of the object. However, I can provide more information. For example, ephemerides published in the US National Air and Space Administration (NASA) give, among other things, the distance of the planet from Earth in AStronome units and its speed, in kilometers per second, due to the ground.
Modern ephemerides are used by professional and amateur astronomers to find objects of interest that can include planetoids and large asteroids, as well as planets. The object can be found in the relevant table for the desired date so that the user knows where to direct the telescope. Ephemerides are also used to render space probes used to explore the solar system planets. The Global Positioning System (GPS) satellites were broadcast by ephemerides and provided their own exact positions at regular intervals.
Because the movements of planets in orbit around the Sun are very predictable, it is possible to assemble ephemerides far into the future. However, the planets are slightly influenced by gravitational moves of numerous asteroids whose exact orbit are not known, so for a very long time the presumed positions can be slightly carried out of step with reality. For this reason are astronomical tabUlky efemeris regularly revised.