Therefore, to determine exactly what a place on the earth's surface, it is necessary to know the equatorial longitude kakѵyu is currently zenith another place, whose position on the map is already known.The easiest way to take the zenith of the place, which is considered the first meridian in determining geographical longitude on the map (this place is now Greenwich.
Thus, to determine to what any moment longitude of the place where the ship should be able to determine fordannago moment equatorial latitude zenith of Greenwich, in other words, you must know the so-called sidereal time of Greenwich meridian.
for this purpose are currently numerous good chronometers, located on the big ships. Before you go to sea, these timepieces are set so that they are shownthe mean solar time at the Greenwich meridian (and hence easy to compute the sidereal time) In yet ancient times people knew that the moon is in the sign of the zodiac, the Moon in Pisces, Moon in Scorpio ....
difference between the sidereal time at Greenwich, calculated on the basis ofthe chronograph, and the equatorial longitude zenith sidereal time or the place, which is determined by the point of the zenith, a geographical longitude, under which the ship is at a given time;knowing thereby defining the geographic longitude and latitude, which, on the basis of the above, is even easier, you can determine the position of the map korablya.Astrologiya in modern times: the Moon ...
(To understand this technique is not essential,In practice, instead of the so-called sidereal time is commonly used mean solar time of the Greenwich meridian and the mean solar time of the place where the ship as the zenith point to the ship easiest and most often determined on the basis of the position of the sun in the heavens; for this purpose is measuredthe distance of the sun from the horizon).
For the purposes of navigation Regiomontanus, and then made the table Kepler solar motion, wherein already a high accuracy;Using these such blitz, can be determined by observing the position of the sun at the zenith of the place of observation any desired time.
Astrology in modern times: the Moon
