Basic definitions of navigation

Hi guys, I came to see you today with a very important article.In this article I hope to bring you some of the key things we need to know when sailing a ship as a sailor.Let's go to the article now

Celestial sphere

The imaginary sphere of infinite radius is centered as the center of the earth.

Celestial poles

The celestial poles are the two points on the celestial sphere where the axis of earth produced would meet celestial sphere.

Equinoctial

The celestial equator is a grate circle on the celestial sphere as the same plane as the plane of the earth's equator thus.Equinoctial is the projection of the equator in the celestial sphere.Every point on the equinoctial in 90° from the celestial poles.Declination are measured north or south from the equinoctial.

Parallel of declination 

Parallel of declination are the small circle on the celestial sphere plane on which are parallel to the plan of the equinoctial.paralleles of the declination corresponds to parallel of latitudes on the earth surface.

Celestial meridians

Celestial Meridians are semi grate circle on the Celestial sphere joining to celestial poles.Celestial meridians cross the equinoctial at rectangles.Celestial Meridian corresponds to meridian on the earth surface.

Ecliptic

Ecliptic is great circle on the celestial sphere in the same plane as the plane of the earth orbit around the sun, thus. The sun apparent anual parth on the celestial sphere is the ecliptic through the earth orbit is an ecliptic.The ecliptic as drown on the the celestial sphere is a grate circle in the same plane as the orbit.

Obliquity of the ecliptic

Obliquity of tje ecliptic is the angle between the plane of the equinoctial and plane of the ecliptic.It´s value approximately 23.5° ( more accurate 23°27´ )

Zodiac

Zodiac is a belt on celestial sphere extending 8° on each side of the ecliptic within reach the sun, the moon and plantes are always found. The belt of the Zodiac is divided into 12 equal part of length 30° each.

            This parts are named after group stars constitution with them.

First part of Aries and first part of Libra

The two parts on the celestial sphere where the ecliptic  intersection.The equinoctial are called the equinoctial point. The point sun appears to cross equinoctial from south to north(spring/vernal equinox) is known as first point of Arie.The point the sun appears to cross equinoctial from north to south is known as first point of Libra.

The observer's Zenith and Nadir

The observer's Zenith

The ponit on celestial sphere vertically above the observer. That is the point at which a straight line from the center of the earth through the observer meet the sphere.

The observer Nadir

The observer's Nadir is the point on Celestial sphere vertically opposite zenith.

Vertical circle 

Vertical circle are grate circle on the celestial sphere passing through the observer's Zenith and Nadir.

Prime vertical circle 

The observer prime vertical is the vertical circle passing through the east and west point of his rational horizon 

Celestial Horizon (Rational Horizon)

The observer's rational horizon is the grate circle on the celestial sphere every point on which is 90° away from his Zenith 

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