128 relations: Abd al-Rahman al-Sufi, Adriaan van Maanen, Alpha Persei Cluster, Annual Review of Astronomy and Astrophysics, Arabic numerals, Astrometry, Astronomical spectroscopy, Astronomical unit, Bayer designation, Beehive Cluster, Beryllium, Big Dipper, Binoculars, Blue straggler, Brown dwarf, Cepheid variable, Charles Messier, Chemical element, Circumstellar disc, Classical Cepheid variable, Comet, Convection, Cosmic distance ladder, Doppler effect, Double Cluster, Earth, Eduard Schönfeld, Edward Emerson Barnard, Ejnar Hertzsprung, Electromagnetic spectrum, Elliptical galaxy, Escape velocity, Extinction (astronomy), Galactic Center, Galactic plane, Galileo Galilei, Giovanni Battista Hodierna, Globular cluster, Gravity, H II region, Half-life, Helium, Hertzsprung–Russell diagram, Hipparcos, Hodge 301, Hyades (star cluster), Hydrogen, Hydrogen line, IC 2391, Infrared dark cloud, ..., Irregular galaxy, Johann Bayer, John Louis Emil Dreyer, John Michell, Kelvin, Kepler-66, Kepler-67, Large Magellanic Cloud, Light-year, List of open clusters, Lithium, Local Group, Main sequence, Messier 41, Messier 47, Messier 7, Metallicity, Metre per second, Milky Way, Molecular cloud, Monthly Notices of the Royal Astronomical Society, Moving-cluster method, Nebula, New General Catalogue, NGC 2244, NGC 2362, NGC 2451, NGC 6811, Nuclear fusion, OB star, Open cluster family, Open cluster remnant, Optical telescope, Parallax, Parsec, Perseus (constellation), Planetary nebula, Pleiades, Projection effect, Proper motion, Ptolemy, R136, Radial velocity, Radiant energy, Radiation pressure, Red giant, Robert Julius Trumpler, Roman numerals, Rosette Nebula, RR Lyrae variable, Scale height, Sidereus Nuncius, Small Magellanic Cloud, Solar mass, Spiral galaxy, Star, Star cluster, Star formation, Stellar association, Stellar evolution, Stellar kinematics, Stellar wind, Supernova, Tarantula Nebula, Taurus (constellation), Telescope, Tidal force, Trigonometry, Ultraviolet, Ursa Major, Ursa Major Moving Group, Vanishing point, Variable star, Velocity, Westerlund 1, White dwarf, Wild Duck Cluster, William Herschel. Expand index (78 more) » « Shrink index
'Abd al-Rahman al-Sufi (عبدالرحمن صوفی (December 7, 903 in Rey, Iran – May 25, 986 in Shiraz, Iran) was a Persian astronomer also known as 'Abd ar-Rahman as-Sufi, 'Abd al-Rahman Abu al-Husayn, 'Abdul Rahman Sufi, or 'Abdurrahman Sufi and, historically, in the West as Azophi and Azophi Arabus. The lunar crater Azophi and the minor planet 12621 Alsufi are named after him. Al-Sufi published his famous Book of Fixed Stars in 964, describing much of his work, both in textual descriptions and pictures. Al-Biruni reports that his work on the ecliptic was carried out in Shiraz. He lived at the Buyid court in Isfahan.
Adriaan van Maanen (March 31, 1884, Sneek – January 26, 1946, Pasadena) was a Dutch–American astronomer.
The Alpha Persei Cluster, also known as Melotte 20 or Collinder 39, is an open cluster in the constellation of Perseus.
The Annual Review of Astronomy and Astrophysics is an annual peer reviewed scientific journal published by Annual Reviews.
Arabic numerals, also called Hindu–Arabic numerals, are the ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, based on the Hindu–Arabic numeral system, the most common system for the symbolic representation of numbers in the world today.
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies.
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light and radio, which radiates from stars and other celestial objects.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name.
The Beehive Cluster (also known as Praesepe (Latin for "manger"), M44, NGC 2632, or Cr 189), is an open cluster in the constellation Cancer.
Beryllium is a chemical element with symbol Be and atomic number 4.
The Big Dipper (US) or the Plough (UK) is an asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude.
Binoculars or field glasses are two telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.
A blue straggler is a main-sequence star in an open or globular cluster that is more luminous and bluer than stars at the main-sequence turn-off point for the cluster.
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter, or approximately to about.
A Cepheid variable is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.
Charles Messier (26 June 1730 – 12 April 1817) was a French astronomer most notable for publishing an astronomical catalogue consisting of nebulae and star clusters that came to be known as the 110 "Messier objects".
A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).
A circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a star.
Classical Cepheids (also known as Population I Cepheids, Type I Cepheids, or Delta Cephei variables) are a type of Cepheid variable star.
A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing.
Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids, including molten rock (rheid).
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects.
The Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave in relation to observer who is moving relative to the wave source.
The Double Cluster (also known as Caldwell 14) is the common name for the open clusters NGC 869 and NGC 884 (often designated h Persei and χ Persei, respectively), which are close together in the constellation Perseus.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Eduard Schönfeld (December 22, 1828 – May 1, 1891) was a German astronomer.
Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer.
Ejnar Hertzsprung (8 October 1873 – 21 October 1967) was a Danish chemist and astronomer born in Copenhagen.
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image.
In physics, escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a massive body.
In astronomy, extinction is the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer.
The Galactic Center is the rotational center of the Milky Way.
The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies.
Galileo Galilei (15 February 1564Drake (1978, p. 1). The date of Galileo's birth is given according to the Julian calendar, which was then in force throughout Christendom. In 1582 it was replaced in Italy and several other Catholic countries with the Gregorian calendar. Unless otherwise indicated, dates in this article are given according to the Gregorian calendar. – 8 January 1642) was an Italian polymath.
Giovanni Battista Hodierna, also spelled as Odierna (April 13, 1597 – April 6, 1660) was an Italian astronomer at the court of Giulio Tomasi, Duke of Palma (Palma di Montechiaro).
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite.
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.
An H II region or HII region is a region of interstellar atomic hydrogen that is ionized.
Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half its initial value.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
The Hertzsprung–Russell diagram, abbreviated H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993.
Hodge 301 is a star cluster in the Tarantula Nebula, visible from Earth's Southern Hemisphere.
The Hyades (Greek Ὑάδες, also known as Melotte 25 or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
Hydrogen is a chemical element with symbol H and atomic number 1.
The hydrogen line, 21-centimeter line or H I line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms.
IC 2391 (also known as the Omicron Velorum Cluster) is an open cluster in the constellation Vela.
An infrared dark cloud (IRDC) is a cold, dense region of a giant molecular cloud.
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy.
Johann Bayer (1572 – 7 March 1625) was a German lawyer and uranographer (celestial cartographer).
John Louis Emil Dreyer (February 13, 1852 – September 14, 1926) was a Danish-Irish astronomer.
John Michell (25 December 1724 – 29 April 1793) was an English natural philosopher and clergyman who provided pioneering insights in a wide range of scientific fields, including astronomy, geology, optics, and gravitation.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
Kepler-66 is a star with slightly more mass than the Sun in the NGC 6811 open cluster in the Cygnus constellation.
Kepler-67 is a star with slightly less mass than the Sun in the NGC 6811 open cluster in the Cygnus constellation and has one confirmed planet, slightly smaller than Neptune, announced in 2013.
The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
This is a list of open clusters located in the Milky Way.
Lithium (from lit) is a chemical element with symbol Li and atomic number 3.
The Local Group is the galaxy group that includes the Milky Way.
In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.
Messier 41 (also known as M41 or NGC 2287) is an open cluster in the Canis Major constellation.
Messier 47 (M47 or NGC 2422) is an open cluster in the constellation Puppis.
Messier 7 or M7, also designated NGC 6475 and sometimes known as the Ptolemy Cluster, is an open cluster of stars in the constellation of Scorpius.
In astronomy, metallicity is used to describe the abundance of elements present in an object that are heavier than hydrogen or helium.
Metre per second (American English: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector quantity which specifies both magnitude and a specific direction), defined by distance in metres divided by time in seconds.
The Milky Way is the galaxy that contains our Solar System.
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2).
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
In astrometry, the moving-cluster method and the closely related convergent point method are means, primarily of historical interest, for determining the distance to star clusters.
A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases.
The New General Catalogue of Nebulae and Clusters of Stars (abbreviated as NGC) is a catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888.
NGC 2244 (also known as Caldwell 50) is an open cluster in the Rosette Nebula, which is located in the constellation Monoceros.
NGC 2362 is an open cluster in the constellation Canis Major.
NGC 2451 is an open cluster in the Puppis constellation, probably discovered by Giovanni Battista Hodierna before 1654 and John Herschel in 1835.
NGC 6811 is an open cluster in the constellation of Cygnus, near the constellation of Lyra.
In nuclear physics, nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles (neutrons or protons).
OB stars are hot, massive stars of spectral types O or early-type B that form in loosely organized groups called OB associations.
In astronomy, an open cluster family is a group of approximately coeval (age range \sim30 Myr) young open star clusters located in a relatively small region of the Galactic disk (radius \sim250 pc).
In astronomy, an open cluster remnant (OCR) is the final stage in the evolution of an open star cluster.
An optical telescope is a telescope that gathers and focuses light, mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct view, or to make a photograph, or to collect data through electronic image sensors.
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
Perseus is a constellation in the northern sky, being named after the Greek mythological hero Perseus.
A planetary nebula, abbreviated as PN or plural PNe, is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
The Pleiades (also known as the Seven Sisters and Messier 45), are an open star cluster containing middle-aged, hot B-type stars located in the constellation of Taurus.
Projection effect may refer to.
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.
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.
R136 (formally known as RMC 136 from the Radcliffe Observatory Magellanic Clouds catalogue) is the central concentration of stars in the NGC 2070 star cluster, which lies at the centre of the Tarantula Nebula in the Large Magellanic Cloud.
The radial velocity of an object with respect to a given point is the rate of change of the distance between the object and the point.
In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic and gravitational radiation.
Radiation pressure is the pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field.
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses) in a late phase of stellar evolution.
Robert Julius Trumpler (until 1915 Robert Trümpler, born October 2, 1886 in Zürich, Switzerland; died September 10, 1956 in Berkeley, United States) was a Swiss-American astronomer.
The numeric system represented by Roman numerals originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages.
The Rosette Nebula (also known as Caldwell 49) is a large spherical H II region (circular in appearance) located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy.
RR Lyrae variables are periodic variable stars, commonly found in globular clusters.
In various scientific contexts, a scale height is a distance over which a quantity decreases by a factor of e (approximately 2.72, the base of natural logarithms).
Sidereus Nuncius (usually Sidereal Messenger, also Starry Messenger or Sidereal Message) is a short astronomical treatise (or pamphlet) published in New Latin by Galileo Galilei on March 13, 1610.
The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, form part of the Hubble sequence.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
Star clusters are groups of stars.
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars.
A stellar association is a very loose star cluster, looser than both open clusters and globular clusters.
Stellar evolution is the process by which a star changes over the course of time.
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space.
A stellar wind is a flow of gas ejected from the upper atmosphere of a star.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
The Tarantula Nebula (also known as 30 Doradus) is an H II region in the Large Magellanic Cloud (LMC).
Taurus (Latin for "the Bull") is one of the constellations of the zodiac, which means it is crossed by the plane of the ecliptic.
A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
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.
Trigonometry (from Greek trigōnon, "triangle" and metron, "measure") is a branch of mathematics that studies relationships involving lengths and angles of triangles.
Ultraviolet (UV) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays.
Ursa Major (also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory.
The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is a nearby stellar moving group – a set of stars with common velocities in space and thought to have a common origin in space and time.
A vanishing point is a point on the image plane of a perspective drawing where the two-dimensional perspective projections (or drawings) of mutually parallel lines in three-dimensional space appear to converge.
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time.
Westerlund 1 (abbreviated Wd1, sometimes called Ara Cluster) is a compact young super star cluster in the Milky Way galaxy, about 3.5–5 kpc away from Earth.
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.
The Wild Duck Cluster (also known as Messier 11, or NGC 6705) is an open cluster in the constellation Scutum.
Frederick William Herschel, (Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer, composer and brother of fellow astronomer Caroline Herschel, with whom he worked.