68 relations: Accuracy and precision, Andrew Claude de la Cherois Crommelin, Angular diameter, Angular momentum, Apsis, Aristarchus of Samos, Astronomical unit, Astronomy, Before Present, Camden House Publishing, Cape of Good Hope, Celestial pole, Corner reflector, Crimean Astrophysical Observatory, Culmination, Distance, Earth, Earth mass, Earth radius, English units, Ephemeris, General relativity, Geodesy, Great circle, Greenwich, Hipparchus, Irene Fischer, Jet Propulsion Laboratory Development Ephemeris, John A. O'Keefe (astronomer), Kilometre, Lidar, Light-second, Lunar eclipse, Lunar Laser Ranging experiment, Lunar theory, Massachusetts Institute of Technology, Mösting (crater), Meridian (astronomy), Metre, Metric system, Mile, Moon, Moon illusion, Near-Earth object, Occultation, On the Sizes and Distances (Aristarchus), Orbit of the Moon, Origin of the Moon, Precambrian, Prutenic Tables, ..., Ptolemy, Regulus, Retroreflector, Royal Radar Establishment, Science (journal), Semi-major and semi-minor axes, SI base unit, Signal-to-noise ratio, Solar mass, Supermoon, Tidal force, Tidal locking, Time of flight, Transit (astronomy), Trigonometry, Unit of measurement, Yarkovsky effect, Zenith. Expand index (18 more) » « Shrink index
Precision is a description of random errors, a measure of statistical variability.
Andrew Claude de la Cherois Crommelin (6 February 1865 – 20 September 1939) was an astronomer of French and Huguenot descent who was born in Cushendun, County Antrim, Ireland.
The angular diameter, angular size, apparent diameter, or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
Aristarchus of Samos (Ἀρίσταρχος ὁ Σάμιος, Aristarkhos ho Samios; c. 310 – c. 230 BC) was an ancient Greek astronomer and mathematician who presented the first known model that placed the Sun at the center of the known universe with the Earth revolving around it (see Solar system).
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Before Present (BP) years is a time scale used mainly in geology and other scientific disciplines to specify when events occurred in the past.
Camden House, Inc. was founded in 1979 by professors James Hardin and Gunther Holst with the purpose of publishing scholarly books in the field of German literature, Austrian Literature, and German language culture.
The Cape of Good Hope (Kaap die Goeie Hoop, Kaap de Goede Hoop, Cabo da Boa Esperança) is a rocky headland on the Atlantic coast of the Cape Peninsula, South Africa.
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.
A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat surfaces, which reflects waves back directly towards the source, but translated.
The Crimean Astrophysical Observatory (CrAO, obs. code: 095) is located at Nauchnij research campus, near the Central Crimean city of Bakhchysarai, on the Crimean peninsula.
In astronomy, the culmination of a planet, star, or constellation is its transit over an observer's meridian.
Distance is a numerical measurement of how far apart objects are.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Earth mass (where ⊕ is the standard astronomical symbol for planet Earth) is the unit of mass equal to that of Earth.
Earth radius is the approximate distance from Earth's center to its surface, about.
English units are the historical units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxon and Roman systems of units.
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.
General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics.
Geodesy, also known as geodetics, is the earth science of accurately measuring and understanding three of Earth's fundamental properties: its geometric shape, orientation in space, and gravitational field.
A great circle, also known as an orthodrome, of a sphere is the intersection of the sphere and a plane that passes through the center point of the sphere.
Greenwich is an area of south east London, England, located east-southeast of Charing Cross.
Hipparchus of Nicaea (Ἵππαρχος, Hipparkhos) was a Greek astronomer, geographer, and mathematician.
Irene Kaminka Fischer (born July 27, 1907 in Vienna, died October 22, 2009 in Boston) was a mathematician, geodesist, National Academy of Engineering Member; Fellow International Geophysical Union, Inductee of the National Imagery and Mapping Agency Hall of Fame.
The name Jet Propulsion Laboratory Development Ephemeris (followed by a number), the abbreviation JPL DE(number), or just DE(number) designates one of a series of models of the Solar System produced at the Jet Propulsion Laboratory in Pasadena, California, primarily for purposes of spacecraft navigation and astronomy.
John Aloysius O'Keefe III (1916–2000) was an expert in planetary science and astrogeology with the National Aeronautics and Space Administration (NASA) from 1958 to 1995.
The kilometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: km; or) or kilometer (American spelling) is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the road network of the United Kingdom where the statute mile is the official unit used.
Lidar (also called LIDAR, LiDAR, and LADAR) is a surveying method that measures distance to a target by illuminating the target with pulsed laser light and measuring the reflected pulses with a sensor.
The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics.
A lunar eclipse occurs when the Moon passes directly behind Earth and into its shadow.
The ongoing Lunar Laser Ranging experiment measures the distance between Earth and the Moon using laser ranging.
Lunar theory attempts to account for the motions of the Moon.
The Massachusetts Institute of Technology (MIT) is a private research university located in Cambridge, Massachusetts, United States.
Mösting is a small lunar impact crater that is located in the southeastern fringes of the Mare Insularum.
In astronomy, the meridian is the great circle passing through the celestial poles, the zenith, and the nadir of an observer's location.
The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit mètre, from the Greek noun μέτρον, "measure") is the base unit of length in some metric systems, including the International System of Units (SI).
The metric system is an internationally adopted decimal system of measurement.
The mile is an English unit of length of linear measure equal to 5,280 feet, or 1,760 yards, and standardised as exactly 1,609.344 metres by international agreement in 1959.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
The Moon illusion is an optical illusion which causes the Moon to appear larger near the horizon than it does higher up in the sky.
A near-Earth object (NEO) is any small Solar System body whose orbit can bring it into proximity with Earth.
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer.
On the Sizes and Distances (of the Sun and Moon) (Περὶ μεγεθῶν καὶ ἀποστημάτων, Peri megethon kai apostematon) is widely accepted as the only extant work written by Aristarchus of Samos, an ancient Greek astronomer who lived circa 310–230 BCE.
The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in about 27.322 days (a sidereal month) and one revolution relative to the Sun in about 29.530 days (a synodic month).
The origin of the Moon is usually thought to be that a Mars-sized body struck the Earth, making a debris ring that eventually collected into a single natural satellite, the Moon, but there are a number of variations on this giant-impact hypothesis, as well as alternate explanations, and research into how the Moon came to be continues.
The Precambrian (or Pre-Cambrian, sometimes abbreviated pЄ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon.
The Prutenic Tables (Tabulae prutenicae from Prutenia meaning "Prussia", Prutenische oder Preußische Tafeln), were an ephemeris (astronomical tables) by the astronomer Erasmus Reinhold published in 1551.
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.
Regulus, also designated Alpha Leonis (α Leonis, abbreviated Alpha Leo, α Leo), is the brightest star in the constellation of Leo and one of the brightest stars in the night sky, lying approximately 79 light years from the Sun.
A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light back to its source with a minimum of scattering.
The Royal Radar Establishment is a research center in Malvern, Worcestershire in the United Kingdom.
Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals.
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter.
The International System of Units (SI) defines seven units of measure as a basic set from which all other SI units can be derived.
Signal-to-noise ratio (abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
A supermoon is a full moon or a new moon that approximately coincides with the closest distance that the Moon reaches to Earth in its elliptic orbit, resulting in a slightly larger-than-usual apparent size of the lunar disk as seen from Earth.
The tidal force is an apparent force that stretches a body towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for the diverse phenomena, including tides, tidal locking, breaking apart of celestial bodies and formation of ring systems within Roche limit, and in extreme cases, spaghettification of objects.
Tidal locking (also called gravitational locking or captured rotation) occurs when the long-term interaction between a pair of co-orbiting astronomical bodies drives the rotation rate of at least one of them into the state where there is no more net transfer of angular momentum between this body (e.g. a planet) and its orbit around the second body (e.g. a star); this condition of "no net transfer" must be satisfied over the course of one orbit around the second body.
Time of flight (TOF) is a property of an object, particle or acoustic, electromagnetic or other wave.
In astronomy, a transit or astronomical transit is the phenomenon of at least one celestial body appearing to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point.
Trigonometry (from Greek trigōnon, "triangle" and metron, "measure") is a branch of mathematics that studies relationships involving lengths and angles of triangles.
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity.
The Yarkovsky effect is a force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum.
The zenith is an imaginary point directly "above" a particular location, on the imaginary celestial sphere.