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M48-done2M.jpgM48.389 viewsMessier 48 (also known as M 48 or NGC 2548) is an open cluster in the Hydra constellation. It was discovered by Charles Messier in 1771.

There is actually no cluster in the position indicated by Messier. The value that he gave for the right ascension matches that of NGC 2548, however, his declination is off by five degrees.Credit for discovery is sometimes given instead to Caroline Herschel in 1783.
MartinJan 29, 2011
Omega-test.jpgOmega Centauri.491 viewsOmega Centauri (ω Cen) or NGC 5139 is a globular cluster[7] seen in the constellation of Centaurus, discovered by Edmond Halley in 1677 who listed it as a nebula. Omega Centauri had been listed in Ptolemy's catalog 2000 years ago as a star. Lacaille included it in his catalog as number I.5. It was first recognized as a globular cluster by the English astronomer John William Herschel in the 1830s.[8] Orbiting the Milky Way, it is both the brightest and the largest known globular cluster associated with our galaxy (1.6 Em). Of all the globular clusters in the Local Group of galaxies, only Mayall II in the Andromeda Galaxy is brighter and more massive.[9] ω Centauri is so different from other galactic globular clusters, that it is thought to be of different origin.[10]

Omega Centauri is located about 15,800 light-years (4,850 pc) from Earth and contains several million Population II stars. The stars in its center are so crowded that they are estimated to average only 0.1 light years away from each other. It is about 12 billion years old
MartinJan 29, 2011
47Tucmoreblue2Gig.jpg47tuc342 viewsfor Trevor :)MartinNov 02, 2010
47Tucreprocessed2Gig.jpg47Tucanae407 viewsThis is an reprocess and has an less green back ground, also the starcolors look better to me.MartinNov 02, 2010
47Tucdone2G.jpg47Tucanae346 views47 Tucanae (NGC 104) or just 47 Tuc is a globular cluster located in the constellation Tucana. It is about 16,700 light years away from Earth, and 120 light years across. It can be seen with the naked eye, with a visual magnitude of 4.0. It's number comes not from the Flamsteed catalogue, but the more obscure 1801 "Allgemeine Beschreibung und Nachweisung der Gestirne nebst Verzeichniss" compiled by Johann Elert Bode.

47 Tucanae was discovered by Nicolas Louis de Lacaille in 1751, its southern location having hidden it from European observers until then. The cluster appears roughly the size of the full moon in the sky under ideal conditions.

It is the second brightest globular cluster in the sky (after Omega Centauri), and is noted for having a very bright and dense core. It has 23 known millisecond pulsars, and at least 21 blue stragglers near the core.
MartinOct 29, 2010
potholomy.jpgNGC6475.354 viewsMessier 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.

The cluster is easily detectable with the naked eye, close to the "stinger" of Scorpius. It has been known since antiquity; it was first recorded by the 1st century astronomer Ptolemy, who described it as a nebula in 130 AD. Giovanni Batista Hodierna observed it before 1654 and counted 30 stars in it. Charles Messier catalogued the cluster in 1764 and subsequently included it in his list of comet-like objects as 'M7'.

Telescopic observations of the cluster reveal about 80 stars within a field of view of 1.3° across. At the cluster's estimated distance of 800-1000 light years this corresponds to an actual diameter of 18-25 light years. The age of the cluster is around 220 million years while the brightest star is of magnitude 5.6.
MartinOct 19, 2010
jewelbox.jpgJewelbox.329 viewsThe Jewel Box (also known as NGC 4755, the Kappa Crucis Cluster and Caldwell 94) is an open cluster in the constellation of Crux. As Kappa Crucis, it has a Bayer designation despite the fact that it is a cluster rather than an individual star.

It is one of the finest open clusters discovered by Nicolas Louis de Lacaille when he was in South Africa during 1751–1752. This cluster is one of the youngest known, with an estimated age of only 7.1 million years. It has an apparent magnitude of 4.2, and is located 6,440 light years from Earth and contains around 100 stars.

This famous group of young bright stars was named the Jewel Box from its description by Sir John Herschel as "a casket of variously coloured precious stones," which refers to its appearance in the telescope. The bright orange star Kappa Crucis contrasts strongly against its predominantly blue, hot companions. Kappa Crucis is a very large (hence very luminous) young star in its red supergiant stage, which paradoxically indicates that its life is drawing to a close. The cluster looks like a star to the unaided eye and appears close to the easternmost star of the Southern Cross, (Beta Crucis), so is only visible from southern latitudes.
MartinOct 19, 2010
6067_done.jpgNGC6067.780 viewsNGC 6067 is a bright open cluster deep South in the Constellation of Norma. Because it is located in the same plane of the Milky Way it has a dense star background. A nice target for small telescopes even from urban skies. The cluster contains about 100 stars between 8 magnitude and fainter.MartinOct 19, 2010
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