40 relations: Almagest, Andromeda Galaxy, Bayer designation, Billion years, Caldwell catalogue, Canis Major Overdensity, Centaurus, Center of mass, Dwarf galaxy, Earth, Edmond Halley, European Southern Observatory, Gemini Observatory, Globular cluster, Hubble Space Telescope, Intermediate-mass black hole, James Dunlop, Jean-Philippe de Chéseaux, Johann Bayer, Kapteyn's Star, Local Group, Mayall II, Messier 54, Metallicity, Milky Way, Monthly Notices of the Royal Astronomical Society, Moon, New General Catalogue, Nicolas-Louis de Lacaille, Parsec, Philosophical Transactions of the Royal Society, Ptolemy, Radial velocity, Sagittarius Dwarf Spheroidal Galaxy, Saint Helena, Solar mass, Stellar population, Uranometria, Velocity dispersion, William H. Keith Jr..
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.
The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to the Milky Way.
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.
A billion years (109 years) is a unit of time on the petasecond scale, more precisely equal to seconds.
The Caldwell Catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers.
The Canis Major Dwarf Galaxy (CMa Dwarf) or Canis Major Overdensity (CMa Overdensity) is a disputed dwarf irregular galaxy in the Local Group, located in the same part of the sky as the constellation Canis Major.
Centaurus is a bright constellation in the southern sky.
In physics, the center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero, or the point where if a force is applied it moves in the direction of the force without rotating.
A dwarf galaxy is a small galaxy composed of about 100 million up to several billion stars, a small number compared to the Milky Way's 200–400 billion stars.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Edmond (or Edmund) Halley, FRS (–) was an English astronomer, geophysicist, mathematician, meteorologist, and physicist.
The European Southern Observatory (ESO) is a 15-nation intergovernmental research organization for ground-based astronomy.
The Gemini Observatory is an astronomical observatory consisting of two 8.19-metre (26.9 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively.
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102-105 solar masses: significantly more than stellar black holes but less than the 105-109 solar mass supermassive black holes.
James Dunlop FRSE (31 October 1793 – 22 September 1848) was a Scottish astronomer, noted for his work in Australia.
Jean-Philippe Loys de Chéseaux (May 4, 1718 in Lausanne – November 30, 1751) was an astronomer from Lausanne in Switzerland.
Johann Bayer (1572 – 7 March 1625) was a German lawyer and uranographer (celestial cartographer).
Kapteyn's Star is a class M1 red subdwarf about 12.76 light years from Earth in the southern constellation Pictor; it is the closest halo star to the Solar System.
The Local Group is the galaxy group that includes the Milky Way.
Mayall II, also known as NGC-224-G1, SKHB 1, GSC 2788:2139, HBK 0-1, M31GC J003247+393440 or Andromeda's Cluster, is a globular cluster orbiting M31, the Andromeda Galaxy.
Messier 54 (also known as M54 or NGC 6715) is a globular cluster in the constellation Sagittarius.
In astronomy, metallicity is used to describe the abundance of elements present in an object that are heavier than hydrogen or helium.
The Milky Way is the galaxy that contains our Solar System.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
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.
Abbé Nicolas-Louis de Lacaille, formerly sometimes spelled de la Caille, (15 March 1713 – 21 March 1762) was a French astronomer.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
Philosophical Transactions, titled Philosophical Transactions of the Royal Society (often abbreviated as Phil. Trans.) from 1776, is a scientific journal published by the Royal Society.
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.
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.
The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way.
Saint Helena is a volcanic tropical island in the South Atlantic Ocean, east of Rio de Janeiro and 1,950 kilometres (1,210 mi) west of the Cunene River, which marks the border between Namibia and Angola in southwestern Africa.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
During 1944, Walter Baade categorized groups of stars within the Milky Way into bluer stars associated with the spiral arms and the general position of yellow stars near the central galactic bulge or within globular star clusters.
Uranometria is the short title of a star atlas produced by Johann Bayer.
In astronomy, the velocity dispersion (σ) is the statistical dispersion of velocities about the mean velocity for a group of objects, such as an open cluster, globular cluster, galaxy, galaxy cluster, or supercluster.
William H. Keith (born August 8, 1950) is an American author, who writes also under several pen names, such as Ian Douglas, Robert Cain and H. Jay Riker.