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98 relations: Al-Battani, Almagest, Almanac, Analemma, Apsis, Astronomer Royal, Astronomical nutation, Axial tilt, Azimuth, Barycenter, Celestial equator, Celestial sphere, Christiaan Huygens, Civil time, Conic section, Constant function, Culmination, Daylight saving time, Declination, Diurnal motion, Dynamical time scale, Earth's orbit, Eccentric anomaly, Eccentricity (mathematics), Ecliptic, Ecliptic coordinate system, Elliptic orbit, Ephemeris, Epoch (astronomy), Equation clock, Equation of the center, Equator, Equinox, Gerald J. Toomer, Gnomon, Gregorian calendar, Heliostat, Hour angle, Jamshīd al-Kāshī, Jeremiah Horrocks, Johannes Kepler, John Flamsteed, Kepler's equation, Kepler's laws of planetary motion, Kushyar Gilani, Longitude, March equinox, Marine chronometer, Mars, Mean, ..., Mean anomaly, Medieval Latin, Meridian (astronomy), Milankovitch cycles, Millisecond, Minute, Mnemonic, Monthly Notices of the Royal Astronomical Society, Muhammad ibn Musa al-Khwarizmi, Nearest integer function, Nevil Maskelyne, Noon, Observatory, Orbital eccentricity, Orbital plane (astronomy), Order of operations, Ordinal date, Perihelion and aphelion, Practical Astronomy with your Calculator, Precession, Ptolemy, Right ascension, Robert Hooke, Root mean square, Royal Observatory, Greenwich, Second, Secular variation, Sidereal time, Sign (mathematics), Solar energy, Solar time, Solar tracker, Solstice, Sun, Sundial, Sunrise, Sunset, Taylor series, The Nautical Almanac, Time zone, Tropical year, True anomaly, Turn (geometry), United States Naval Observatory, Universal joint, Universal Time, Uranus, Year. Expand index (48 more) »
Al-Battani
Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī (Arabic: محمد بن جابر بن سنان البتاني) (Latinized as Albategnius, Albategni or Albatenius) (c. 858 – 929) was an Arab astronomer, astrologer, and mathematician.
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Almagest
The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy. One of the most influential scientific texts of all time, its geocentric model was accepted for more than 1200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus.
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Almanac
An almanac (also spelled almanack and almanach) is an annual publication listing a set of events forthcoming in the next year.
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Analemma
In astronomy, an analemma (from Greek ἀνάλημμα analēmma "support") is a diagram showing the variation of the position of the Sun in the sky over the course of a year, as viewed at a fixed time of day and from a fixed location on the Earth.
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Apsis
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
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Astronomer Royal
Astronomer Royal is a senior post in the Royal Households of the United Kingdom.
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Astronomical nutation
Astronomical nutation is a phenomenon which causes the orientation of the axis of rotation of a spinning astronomical object to vary over time.
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Axial tilt
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, or, equivalently, the angle between its equatorial plane and orbital plane.
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Azimuth
An azimuth (from the pl. form of the Arabic noun "السَّمْت" as-samt, meaning "the direction") is an angular measurement in a spherical coordinate system.
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Barycenter
The barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον centre) is the center of mass of two or more bodies that are orbiting each other, which is the point around which they both orbit.
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Celestial equator
The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth.
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Celestial sphere
In astronomy and navigation, the celestial sphere is an abstract sphere with an arbitrarily large radius concentric to Earth.
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Christiaan Huygens
Christiaan Huygens (Hugenius; 14 April 1629 – 8 July 1695) was a Dutch physicist, mathematician, astronomer and inventor, who is widely regarded as one of the greatest scientists of all time and a major figure in the scientific revolution.
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Civil time
In modern usage, civil time refers to statutory time scales designated by civilian authorities, or to local time indicated by clocks.
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Conic section
In mathematics, a conic section (or simply conic) is a curve obtained as the intersection of the surface of a cone with a plane.
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Constant function
In mathematics, a constant function is a function whose (output) value is the same for every input value.
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Culmination
In astronomy, the culmination of a planet, star, or constellation is its transit over an observer's meridian.
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Daylight saving time
Daylight saving time (abbreviated DST), sometimes referred to as daylight savings time in U.S., Canadian, and Australian speech, and known as summer time in some countries, is the practice of advancing clocks during summer months so that evening daylight lasts longer, while sacrificing normal sunrise times.
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Declination
In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle.
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Diurnal motion
Diurnal motion (lit, from dies, lit. "day") is an astronomical term referring to the apparent daily motion of stars around Earth, or more precisely around the two celestial poles.
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Dynamical time scale
In time standards, dynamical time is the time-like argument of a dynamical theory; and a dynamical time scale in this sense is the realization of a time-like argument based on a dynamical theory: that is, the time and time scale are defined implicitly, inferred from the observed position of an astronomical object via a theory of its motion.
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Earth's orbit
Earth's orbit is the trajectory along which Earth travels around the Sun.
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Eccentric anomaly
In orbital mechanics, eccentric anomaly is an angular parameter that defines the position of a body that is moving along an elliptic Kepler orbit.
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Eccentricity (mathematics)
In mathematics, the eccentricity, denoted e or \varepsilon, is a parameter associated with every conic section.
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Ecliptic
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.
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Ecliptic coordinate system
The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions and orbits of Solar System objects.
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Elliptic orbit
In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0.
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Ephemeris
In astronomy and celestial navigation, an ephemeris (plural: ephemerides) gives the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times.
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Epoch (astronomy)
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.
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Equation clock
An equation clock is a mechanical clock which includes a mechanism that simulates the equation of time, so that the user can read or calculate solar time, as would be shown by a sundial.
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Equation of the center
In two-body, Keplerian orbital mechanics, the equation of the center is the angular difference between the actual position of a body in its elliptical orbit and the position it would occupy if its motion were uniform, in a circular orbit of the same period.
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Equator
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel).
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Equinox
An equinox is commonly regarded as the moment the plane (extended indefinitely in all directions) of Earth's equator passes through the center of the Sun, which occurs twice each year, around 20 March and 22-23 September.
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Gerald J. Toomer
Gerald James Toomer (born 23 November 1934) is a historian of astronomy and mathematics who has written numerous books and papers on ancient Greek and medieval Islamic astronomy.
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Gnomon
A gnomon (from Greek γνώμων, gnōmōn, literally: "one that knows or examines") is the part of a sundial that casts a shadow.
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Gregorian calendar
The Gregorian calendar is the most widely used civil calendar in the world.
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Heliostat
A heliostat (from helios, the Greek word for sun, and stat, as in stationary) is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky.
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Hour angle
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.
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Jamshīd al-Kāshī
Ghiyāth al-Dīn Jamshīd Masʿūd al-Kāshī (or al-Kāshānī) (غیاث الدین جمشید کاشانی Ghiyās-ud-dīn Jamshīd Kāshānī) (c. 1380 Kashan, Iran – 22 June 1429 Samarkand, Transoxania) was a Persian astronomer and mathematician.
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Jeremiah Horrocks
Jeremiah Horrocks (1618 – 3 January 1641), sometimes given as Jeremiah Horrox (the Latinised version that he used on the Emmanuel College register and in his Latin manuscripts), – See footnote 1 was an English astronomer.
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Johannes Kepler
Johannes Kepler (December 27, 1571 – November 15, 1630) was a German mathematician, astronomer, and astrologer.
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John Flamsteed
John Flamsteed FRS (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal.
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Kepler's equation
In orbital mechanics, Kepler's equation relates various geometric properties of the orbit of a body subject to a central force.
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Kepler's laws of planetary motion
In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.
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Kushyar Gilani
Abul-Hasan Kūshyār ibn Labbān ibn Bashahri Gilani (971–1029), also known as Kūshyār Gīlānī (کوشیار گیلانی), was an Iranian mathematician, geographer, and astronomer from Gilan, south of the Caspian Sea, Iran.
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Longitude
Longitude, is a geographic coordinate that specifies the east-west position of a point on the Earth's surface.
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March equinox
The March equinox or Northward equinox is the equinox on the Earth when the subsolar point appears to leave the southern hemisphere and cross the celestial equator, heading northward as seen from Earth.
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Marine chronometer
A marine chronometer is a timepiece that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation.
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Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.
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Mean
In mathematics, mean has several different definitions depending on the context.
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Mean anomaly
In celestial mechanics, the mean anomaly is an angle used in calculating the position of a body in an elliptical orbit in the classical two-body problem.
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Medieval Latin
Medieval Latin was the form of Latin used in the Middle Ages, primarily as a medium of scholarly exchange, as the liturgical language of Chalcedonian Christianity and the Roman Catholic Church, and as a language of science, literature, law, and administration.
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Meridian (astronomy)
In astronomy, the meridian is the great circle passing through the celestial poles, the zenith, and the nadir of an observer's location.
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Milankovitch cycles
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years.
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Millisecond
A millisecond (from milli- and second; symbol: ms) is a thousandth (0.001 or 10−3 or 1/1000) of a second.
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Minute
The minute is a unit of time or angle.
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Mnemonic
A mnemonic (the first "m" is silent) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory.
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Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
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Muhammad ibn Musa al-Khwarizmi
There is some confusion in the literature on whether al-Khwārizmī's full name is ابو عبد الله محمد بن موسى الخوارزمي or ابو جعفر محمد بن موسی الخوارزمی.
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Nearest integer function
In computer science, the nearest integer function of real number x denoted variously by, \lfloor x \rceil, \Vert x \Vert, nint(x), or Round(x), is a function which returns the nearest integer to x. To avoid ambiguity when operating on half-integers, a rounding rule must be chosen.
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Nevil Maskelyne
The Rev Dr Nevil Maskelyne DD FRS FRSE (6 October 1732 – 9 February 1811) was the fifth British Astronomer Royal.
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Noon
Noon (also midday or noon time) is 12 o'clock in the daytime, as opposed to midnight.
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Observatory
An observatory is a location used for observing terrestrial or celestial events.
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Orbital eccentricity
The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.
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Orbital plane (astronomy)
The orbital plane of a revolving body is the geometric plane on which its orbit lies.
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Order of operations
In mathematics and computer programming, the order of operations (or operator precedence) is a collection of rules that reflect conventions about which procedures to perform first in order to evaluate a given mathematical expression.
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Ordinal date
An ordinal date is a calendar date typically consisting of a year and a day of year ranging between 1 and 366 (starting on January 1), though year may sometimes be omitted.
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Perihelion and aphelion
The perihelion of any orbit of a celestial body about the Sun is the point where the body comes nearest to the Sun.
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Practical Astronomy with your Calculator
Practical Astronomy with your Calculator is a book written by Peter Duffett-Smith, a University Lecturer and a Fellow of Downing College.
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Precession
Precession is a change in the orientation of the rotational axis of a rotating body.
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Ptolemy
Claudius Ptolemy (Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos; Claudius Ptolemaeus) was a Greco-Roman mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology.
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Right ascension
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.
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Robert Hooke
Robert Hooke FRS (– 3 March 1703) was an English natural philosopher, architect and polymath.
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Root mean square
In statistics and its applications, the root mean square (abbreviated RMS or rms) is defined as the square root of the mean square (the arithmetic mean of the squares of a set of numbers).
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Royal Observatory, Greenwich
The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, moved from Greenwich to Herstmonceux) is an observatory situated on a hill in Greenwich Park, overlooking the River Thames.
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Second
The second is the SI base unit of time, commonly understood and historically defined as 1/86,400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.
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Secular variation
The secular variation of a time series is its long-term non-periodic variation (see Decomposition of time series).
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Sidereal time
Sidereal time is a timekeeping system that astronomers use to locate celestial objects.
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Sign (mathematics)
In mathematics, the concept of sign originates from the property of every non-zero real number of being positive or negative.
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Solar energy
Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis.
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Solar time
Solar time is a calculation of the passage of time based on the position of the Sun in the sky.
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Solar tracker
A solar tracker is a device that orients a payload toward the Sun.
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Solstice
A solstice is an event occurring when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere.
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Sun
The Sun is the star at the center of the Solar System.
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Sundial
A sundial is a device that tells the time of day when there is sunlight by the apparent position of the Sun in the sky.
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Sunrise
Sunrise or sun up is the instant at which the upper edge of the Sun appears over the horizon in the morning.
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Sunset
Sunset or sundown is the daily disappearance of the Sun below the horizon as a result of Earth's rotation.
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Taylor series
In mathematics, a Taylor series is a representation of a function as an infinite sum of terms that are calculated from the values of the function's derivatives at a single point.
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The Nautical Almanac
The Nautical Almanac has been the familiar name for a series of official British almanacs published under various titles since the first issue of The Nautical Almanac and Astronomical Ephemeris, for 1767: this was the first nautical almanac ever to contain data dedicated to the convenient determination of longitude at sea.
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Time zone
A time zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes.
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Tropical year
A tropical year (also known as a solar year) is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice.
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True anomaly
In celestial mechanics, true anomaly is an angular parameter that defines the position of a body moving along a Keplerian orbit.
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Turn (geometry)
A turn is a unit of plane angle measurement equal to 2pi radians, 360 degrees or 400 gradians.
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United States Naval Observatory
The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense.
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Universal joint
A universal joint (universal coupling, U-joint, Cardan joint, Spicer or Hardy Spicer joint, or Hooke's joint) is a joint or coupling connecting rigid rods whose axes are inclined to each other, and is commonly used in shafts that transmit rotary motion.
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Universal Time
Universal Time (UT) is a time standard based on Earth's rotation.
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Uranus
Uranus is the seventh planet from the Sun.
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Year
A year is the orbital period of the Earth moving in its orbit around the Sun.
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References
[1] https://en.wikipedia.org/wiki/Equation_of_time
