Search results
Results from the WOW.Com Content Network
The first known globular cluster, now called M 22, was discovered in 1665 by Abraham Ihle, a German amateur astronomer. [4] [5] [6] The cluster Omega Centauri, easily visible in the southern sky with the naked eye, was known to ancient astronomers like Ptolemy as a star, but was reclassified as a nebula by Edmond Halley in 1677, [7] then finally as a globular cluster in the early 19th century ...
These are globular clusters within the halo of the Milky Way galaxy. The diameter is in minutes of arc as seen from Earth. For reference, the J2000 epoch celestial coordinates of the Galactic Center are right ascension 17h 45m 40.04s, declination −29° 00′ 28.1″. A high proportion of globular clusters are located in the Ophiuchus and ...
Other designations. NGC 7089 [8] See also: Globular cluster, List of globular clusters. Messier 2 or M2 (also designated NGC 7089) is a globular cluster in the constellation Aquarius, five degrees north of the star Beta Aquarii. It was discovered by Jean-Dominique Maraldi in 1746, and is one of the largest known globular clusters.
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. A direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth.
In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables, sometimes called the Leavitt Law. [2][3][4] Discovered in 1908 by Henrietta Swan Leavitt, the relation ...
Messier 3 is the prototype for the Oosterhoff type I cluster, which is considered "metal-rich". That is, for a globular cluster, Messier 3 has a relatively high abundance of heavier elements. [15] Arcturus and Cor Caroli can be used to help locate M3.
Messier 13 was discovered by Edmond Halley in 1714, [ 2 ] and cataloged by Charles Messier on June 1, 1764, [ 9 ] into his list of objects not to mistake for comets; Messier's list, including Messier 13, eventually became known as the Messier catalog. [ 10 ] It is located at right ascension 16 h 41.7 m, declination +36° 28'.
NGC 6426 is a globular cluster of stars located in the equatorial constellation of Ophiuchus. It was discovered by the German-English astronomer William Herschel on 3 June 1786. [ 7 ] This cluster is at a distance of 67,000 light years from the Sun. [ 3 ] It has an apparent visual magnitude of 10.9 and an angular diameter of 4.2 ′ , making it ...