Northern celestial hemisphereThe northern celestial hemisphere, also called the Northern Sky, is the northern half of the celestial sphere; that is, it lies north of the celestial equator. This arbitrary sphere appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Northern Sky is visible from the geographic North Pole, while less of the hemisphere is visible the farther south the observer is located.Celestial poleThe north and south celestial poles are the two points in the sky where Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently directly overhead to observers at Earth's North Pole and South Pole, respectively.
Celestial equatorThe celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of a planet, by convention generally Earth. By extension, it is also a plane of reference in the equatorial coordinate system.
Celestial sphereIn astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, which may be centered on Earth or the observer. If centered on the observer, half of the sphere would resemble a hemispherical screen over the observing location.
Southern HemisphereThe Southern Hemisphere is the half (hemisphere) of Earth that is south of the equator.
Fixed starsIn astronomy, the fixed stars (Latin: stellae fixae) are the lights (luminary points), mainly stars visible to the naked eye, that appear not to move relative to each other against the dark background of the night sky. They are defined in contrast to lights that appear to move relative to each other and to the fixed stars, which include classical planets and comets.
ConstellationA constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellations were likely defined in prehistory. People used them to relate stories of their beliefs, experiences, creation, and mythology.
SouthSouth is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. EtymologyThe word south comes from Old Englishsūþ, from earlier Proto-Germanic*sunþaz ("south"), possibly related to the same Proto-Indo-European root that the word sun derived from.
Earth's rotationEarth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar starPolaris, Earth turns counterclockwise. The North Pole, also called the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere at which Earth's axis of rotation meets its surface.
South PoleThe South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is the point in the Southern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True South Pole to distinguish from the south magnetic pole. The South Pole is by definition the southernmost point on the Earth, lying antipodally to the North Pole. It defines geodetic latitude 90° South, as well as the direction of true south.
Diurnal motionIn astronomy, diurnal motion (from Latin diurnus 'daily', from Latin diēs 'day') is the apparent motion of celestial objects (e.g. the Sun and stars) around Earth, or more precisely around the two celestial poles, over the course of one day. It is caused by Earth's rotation around its axis, so almost every star appears to follow a circular arc path, called the diurnal circle, often depicted in star trail photography.
LatitudeInternational Terrestrial Reference SystemSpatial Reference System Identifier (SRID)Universal Transverse Mercator (UTM)*As an Amazon Associate I earn from qualifying purchases.