NGC 5694 | |
---|---|
Observation data (J2000 epoch) | |
Class | VII [1] |
Constellation | Hydra |
Right ascension | 14h 39m 36.5s [2] |
Declination | −26° 32′ 18.0″ [2] |
Distance | 114,100ly [1] |
Apparent magnitude (V) | 10.2 [1] |
Apparent dimensions (V) | 3.6′ [1] |
Physical characteristics | |
Metallicity | = –1.74 [3] dex |
Estimated age | 13.44 Gyr [3] |
Other designations | Caldwell 66 |
NGC 5694 (also known as Caldwell 66) is a globular cluster in the constellation Hydra. It was discovered in 1784 by William Herschel.
This globular cluster is located at a distance of 114,000 light-years (35,000 pc) from the Sun and 96,000 light-years (29,000 pc) from the Galactic Center [4] and is one of the oldest known globular clusters in the Milky Way Galaxy, forming nearly 12 billion years ago. [5]
Its chemical composition is highly peculiar, being highly (to nearly solar levels) enriched in alpha elements, suggesting an extragalactic origin before being captured by the Milky Way. [6]
Messier 5 or M5 is a globular cluster in the constellation Serpens. It was discovered by Gottfried Kirch in 1702.
Messier 107 or M107, also known as NGC 6171, is a very loose globular cluster in a very mildly southern part of the sky close to the equator in Ophiuchus, and is the last such object in the Messier Catalogue.
Messier 80 is a globular cluster in the constellation Scorpius. It was discovered by Charles Messier in 1781, being one of his first discoveries.
Messier 12 or M 12 is a globular cluster in the constellation of Ophiuchus. It was discovered by the French astronomer Charles Messier on May 30, 1764, who described it as a "nebula without stars". In dark conditions this cluster can be faintly seen with a pair of binoculars. Resolving the stellar components requires a telescope with an aperture of 8 in (20 cm) or greater. In a 10 in (25 cm) scope, the granular core shows a diameter of 3′ (arcminutes) surrounded by a 10′ halo of stars.
Messier 30 is a globular cluster of stars in the southeast of the southern constellation of Capricornus, at about the declination of the sun when the latter is at December solstice. It was discovered by the French astronomer Charles Messier in 1764, who described it as a circular nebula without a star. In the New General Catalogue, compiled during the 1880s, it was described as a "remarkable globular, bright, large, slightly oval." It can be easily viewed with a pair of 10×50 binoculars, forming a patch of hazy light some 4 arcminutes wide that is slightly elongated along the east–west axis. With a larger instrument, individual stars can be resolved and the cluster will cover an angle of up to 12 arcminutes across graduating into a compressed core about one arcminute wide that has further star density within.
Messier 53 is a globular cluster in the Coma Berenices constellation. It was discovered by Johann Elert Bode in 1775. M53 is one of the more outlying globular clusters, being about 60,000 light-years (18.4 kpc) light-years away from the Galactic Center, and almost the same distance from the Solar System. The cluster has a core radius (rc) of 2.18 pc, a half-light radius (rh) of 5.84 pc, and a tidal radius (rtr) of 239.9 pc.
Messier 62 or M62, also known as NGC 6266, is a globular cluster of stars in the south of the equatorial constellation of Ophiuchus. It was discovered in 1771 by Charles Messier, then added to his catalogue eight years later.
Messier 69 or M69, also known NGC 6637, is a globular cluster in the southern constellation of Sagittarius. It can be found 2.5° to the northeast of the star Epsilon Sagittarii and is dimly visible in 50 mm aperture binoculars. The cluster was discovered by Charles Messier on August 31, 1780, the same night he discovered M70. At the time, he was searching for an object described by Nicolas-Louis de Lacaille in 1751–2 and thought he had rediscovered it, but it is unclear if Lacaille actually described M69.
Messier 70 or M70, also known as NGC 6681, is a globular cluster of stars to be found in the south of Sagittarius. It was discovered by Charles Messier in 1780. The famous comet Hale–Bopp was discovered near this cluster in 1995.
NGC 2419 is a globular cluster in the constellation Lynx. It was discovered by William Herschel on December 31, 1788. NGC 2419 is at a distance of about 300,000 light years from the Solar System and at the same distance from the Galactic Center.
NGC 6712 is a globular cluster that was probably discovered by Le Gentil on July 9, 1749 when investigating the Milky Way star cloud in Aquila. He described it as a "true nebula," in contrast to the open star cluster M11. Independently discovered by William Herschel on June 16, 1784 and cataloged as H I.47; he also first classified it as a round nebula. John Herschel was the first to describe it as a globular star cluster during his observations in the 1830s. The cluster appears to be about 12 billion years old and may have originally have been significantly more massive having undergone significant mass loss due to passes through the galactic disc. For a globular cluster, NGC 6712 is somewhat metal-rich.
NGC 288 is a globular cluster in the constellation Sculptor. Its visual appearance was described by John Dreyer in 1888. It is located about 1.8° southeast of the galaxy NGC 253, 37′ north-northeast of the South Galactic Pole, 15′ south-southeast of a 9th magnitude star, and encompassed by a half-circular chain of stars that opens on its southwest side. It can be observed through binoculars. It is not very concentrated and has a well resolved, large 3′ dense core that is surrounded by a much more diffuse and irregular 9′ diameter ring. Peripheral members extend farther outward towards the south and especially southwest.
NGC 6752 is a globular cluster in the constellation Pavo. It is the fourth-brightest globular cluster in the sky, after Omega Centauri, 47 Tucanae and Messier 22, respectively. It is best seen from June to October in the Southern Hemisphere.
NGC 362 is a globular cluster located in the constellation Tucana in the Southern Hemisphere, slightly north of the Small Magellanic Cloud, to which it is completely unrelated. It was discovered on August 1, 1826 by James Dunlop. It is visible to the naked eye in dark skies, and is an impressive sight in a telescope, although it is somewhat overshadowed by its larger and brighter neighbour 47 Tucanae.
NGC 1261 is a globular cluster of stars in the southern constellation of Horologium, first discovered by Scottish astronomer James Dunlop in 1826. The cluster is located at a distance of 53 kilolight-years from the Sun, and 59 kilolight-years from the Galactic Center. It is about 10.24 billion years old with 341,000 times the mass of the Sun. The cluster does not display the normal indications of core collapse, but evidence suggests it may have instead passed through a post core-collapse bounce state within the past two billion years. The central luminosity density is 2.22 L☉·pc−3, which is low for a globular cluster. Despite this, it has a Shapley–Sawyer Concentration Class of II, indicating a dense central concentration.
NGC 6352 is a globular cluster of stars in the southern constellation of Ara, located approximately 18.3 kly from the Sun. It was discovered by Scottish astronomer James Dunlop on May 14, 1826. The cluster has a Shapley–Sawyer Concentration Class of XI:. A telescope with a 15 cm (5.9 in) aperture is required to resolve the stars within this loose cluster.
NGC 6496 is a globular cluster which is in the direction of the Milky Way's galactic bulge based on observations collected with the WFPC2 on board the Hubble Space Telescope. NGC 6496 was originally believed to be a member of the disc system of the Galactic Center, but scientists questioned this classification. It was instead suggested that NGC 6496, together with two other clusters, NGC 6624 and NGC 6637, could be halo clusters with strongly inclined orbits. NGC 6496 lies in the Southern sky at RA=17:59:03.68 and Dec=-44:15:57.4.
NGC 6101 is a globular cluster in the constellation Apus, which was discovered by James Dunlop and catalogued by him as Δ68. It is located at a distance of about 47,600 light-years from the Sun and about 36,500 light-years from the Galactic Center of the Milky Way. It requires a telescope of at least 20 cm (7.9 in) aperture to resolve individual stars. Research revealed this cluster to contain an unexpected large number of black holes.
NGC 5286 is a globular cluster of stars located some 35,900 light years away in the constellation Centaurus. At this distance, the light from the cluster has undergone reddening from interstellar gas and dust equal to E(B – V) = 0.24 magnitude in the UBV photometric system. The cluster lies 4 arc-minutes north of the naked-eye star M Centauri. It was discovered by Scottish astronomer James Dunlop, active in Australia, and listed in his 1827 catalog.
NGC 4372 is a globular cluster in the southern constellation of Musca. It is southwest of γ Muscae and west of the southern end of the Dark Doodad Nebula, a 3° thin streak of black across a southern section of the great plane of the Milky Way.