Home > Positional astronomy
Positional astronomy is the study of the positions of celestial objects. This is the oldest branch of astronomy and dates back to antiquity. Observations of celestial objects are important for religious and astrological purposes, as well as for timekeeping.The science of actually measuring positions of celestial objects in the sky is known as astrometry.
Ancient structures associated with positional astronomy include:
The unaided human eye can detect about 6000 stars, of which about half are below the horizon at any one time.
On modern star charts, the celestial sphere is divided into 88 constellations. Every star lies within a constellation.
Constellations are useful for navigation. If you live in the northern hemisphere you can find north by locating the star Polaris. This star is always at a position nearly over the north pole.
See also:
- Planets which are in conjunction form a line which passes through the center of the solar systemA generic solar system (or planetary system consists of at least one star and various orbiting objects (such as asteroids, comets, moons, and planets). The term originated to describe the planetary system around Sol, the Latin name for our sun. The planet
- The eclipticThe ecliptic is the geometric plane that contains the orbit of the Earth. The orbits of most planets in the Solar System lie very close to it. Seen from the Earth, this is a bisecting great circle, superimposed upon the celestial sphere, which contains th is the planeIn mathematics, a plane is the fundamental two-dimensional object. Intuitively, it may be visualized as a flat infinite piece of paper. Most of the fundamental work in geometry, trigonometry, and graphing is performed in two dimensions, or in other words, which contains the orbit of a planet, usually in reference to EarthEarth also known as the Earth or Terra is the planet on which we live, the third planet outward from the Sun. It is the largest of the solar system's terrestrial planets, and the only planetary body that modern science confirms as harbouring life. The pla
- ElongationElongation is an astronomical term that refers to the angle between the Sun and a planet, as viewed from Earth. When an inferior planet is visible after sunset, it is near its greatest eastern elongation . When an inferior planet is visible before sunrise refers to the angleThis article is about angles in geometry. For other articles, see Angle (disambiguation An angle (from the Lat. angulus a corner, a diminutive, of which the primitive form, angus does not occur in Latin; cognate are the Lat. angere, to compress into a ben formed by a planet, with respect to the system's center and a viewing pointThe word point can refer to: a location in physical space a unit of angular measurement; see navigation point is a typographic unit of measure in typography equal inch or sometimes approximated as inch; on computer displays it should be equal to point in
- Superior planetsThe terms inferior planet and superior planet were coined by Copernicus to distinguish a planet's orbit's size in relation to the Earth's. Inferior planet" is used in reference to Mercury and Venus, which are closer to the Sun than the Earth is. Superior have a larger orbit than the earth while the inferior planets (Mercury and Venus) orbit the sun inside the earth's orbit
- A transit occurs when an inferior planet passes through a point of conjunction
