52 relations: Antarctic, Antarctic Circle, Arctic, Arctic Circle, Astronomy, Atmospheric refraction, Axial precession, Brady Haran, Celestial coordinate system, Celestial equator, Celestial pole, Celestial sphere, Circumpolar star, Degree (angle), Ecliptic, Epoch (astronomy), Equator, Equatorial coordinate system, Geographic coordinate system, Geographical pole, Horizon, Hour angle, Hour circle, Latitude, Lunar standstill, Midnight, Midnight sun, Minute and second of arc, Negative number, Northern Hemisphere, Orbit, Polar night, Pole star, Position of the Sun, Proper motion, Right ascension, Sea level, Season, Setting circles, Sexagesimal, Solar System, Southern Hemisphere, Star, Stellar parallax, Summer solstice, Terrestrial Time, Tropic of Cancer, Tropic of Capricorn, U.S. National Geodetic Survey, University of Nottingham, ..., Vertical deflection, 45th parallel north. Expand index (2 more) » « Shrink index
The Antarctic (US English, UK English or and or) is a polar region around the Earth's South Pole, opposite the Arctic region around the North Pole.
The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of the Earth.
The Arctic is a polar region located at the northernmost part of Earth.
The Arctic Circle is the most northerly of the five major circles of latitude as shown on maps of Earth.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height.
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis.
Brady John Haran (born 18 June 1976) is an Australian-born British independent filmmaker and video journalist who is known for his educational videos and documentary films produced for BBC News and his YouTube channels, the most notable being Periodic Videos and Numberphile.
In astronomy, a celestial coordinate system is a system for specifying positions of celestial objects: satellites, planets, stars, galaxies, and so on.
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth.
The north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere.
In astronomy and navigation, the celestial sphere is an abstract sphere with an arbitrarily large radius concentric to Earth.
A circumpolar star is a star, as viewed from a given latitude on Earth, that never sets below the horizon due to its apparent proximity to one of the celestial poles.
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane angle, defined so that a full rotation is 360 degrees.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel).
The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects.
A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols.
A geographical pole is either of the two points on a rotating body (planet, dwarf planet, natural satellite, sphere...etc) where its axis of rotation intersects its surface.
The horizon or skyline is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not.
In astronomy and celestial navigation, the hour angle is one of the coordinates used in the equatorial coordinate system to give the direction of a point on the celestial sphere.
In astronomy, the hour circles, which together with declination and distance (from the centre of mass of the planet) locate any celestial object, is the great circle through the object and the two celestial poles.
In geography, latitude is a geographic coordinate that specifies the north–south position of a point on the Earth's surface.
At a major lunar standstill, which takes place every 18.6 years, the Moon's range of declination, and consequently its range of azimuth at moonrise and moonset, reaches a maximum.
Midnight is the transition time from one day to the next – the moment when the date changes.
The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the sun remains visible at the local midnight.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
In mathematics, a negative number is a real number that is less than zero.
The Northern Hemisphere is the half of Earth that is north of the Equator.
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.
The polar night occurs in the northernmost and southernmost regions of the Earth when the night lasts for more than 24 hours.
Pole star or polar star refers to a star, preferably bright, closely aligned to the axis of rotation of an astronomical object.
The position of the Sun in the sky is a function of both the time and the geographic location of observation on Earth's surface.
Proper motion is the astronomical measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.
Right ascension (abbreviated RA; symbol) is the angular distance measured only eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point above the earth in question.
Mean sea level (MSL) (often shortened to sea level) is an average level of the surface of one or more of Earth's oceans from which heights such as elevations may be measured.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight.
Setting circles are used on telescopes equipped with an equatorial mount to find astronomical objects in the sky by their equatorial coordinates often used in star charts or ephemerides.
Sexagesimal (base 60) is a numeral system with sixty as its base.
The Solar SystemCapitalization of the name varies.
The Southern Hemisphere is the half of Earth that is south of the Equator.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.
The summer solstice (or estival solstice), also known as midsummer, occurs when one of the Earth's poles has its maximum tilt toward the Sun.
Terrestrial Time (TT) is a modern astronomical time standard defined by the International Astronomical Union, primarily for time-measurements of astronomical observations made from the surface of Earth.
The Tropic of Cancer, also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead.
The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point on the December (or southern) solstice.
The National Geodetic Survey (NGS), formerly the United States Survey of the Coast (1807–1836), United States Coast Survey (1836–1878), and United States Coast and Geodetic Survey (USC&GS) (1878–1970), is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications of science and engineering.
The University of Nottingham is a public research university in Nottingham, United Kingdom.
The vertical deflection (deflection of the plumb line, astro-geodetic deflection) at a point on the Earth is a measure of how far the direction of the local gravity field has been shifted by local anomalies such as nearby mountains.
The 45th parallel north is a circle of latitude that is 45 degrees north of Earth's equator.