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etaha-2.jpg
etaha-2.jpgEta Carinae in HA.578 viewsThis stellar system is currently one of the most massive that can be studied in great detail. Until recently, Eta Carinae was thought to be the most massive single star, but it was recently demoted to a binary system.[7] The most massive star in the Eta Carinae multiple star system has more than 100 times the mass of the Sun. Other known massive stars are more luminous and more massive.

Stars in the mass class of Eta Carinae, with more than 100 times the mass of the Sun, produce more than a million times as much light as the Sun. They are quite rare — only a few dozen in a galaxy as big as the Milky Way. They are assumed to approach (or potentially exceed) the Eddington limit, i.e., the outward pressure of their radiation is almost strong enough to counteract gravity. Stars that are more than 120 solar masses exceed the theoretical Eddington limit, and their gravity is barely strong enough to hold in their radiation and gas.

Eta Carinae's chief significance for astrophysics is based on its giant eruption or supernova impostor event, which was observed around 1843. In a few years, Eta Carinae produced almost as much visible light as a supernova explosion, but it survived. Other supernova impostors have been seen in other galaxies, for example the false supernovae SN 1961v in NGC 1058[8] and SN 2006jc in UGC 4904,[9] which produced a false supernova, noted in October 2004. Significantly, SN 2006jc was destroyed in a supernova explosion two years later, observed on October 9, 2006.[10] The supernova impostor phenomenon may represent a surface instability[11] or a failed supernova. Eta Carinae's giant eruption was the prototype for this phenomenon, and after nearly 170 years the star's internal structure has not fully recovered.
Martin
Lagoondone2Mb.jpg
Lagoondone2Mb.jpgLagoon nebula680 viewsDone with the ED100 and Hutech FR/FF.Martin
Dougs_scope.jpg
Dougs_scope.jpg448 viewsMartin
potholomy.jpg
potholomy.jpgNGC6475.527 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.
Martin
47Tucdone2G.jpg
47Tucdone2G.jpg47Tucanae521 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.
Martin
Jen_preparing.jpg
Jen_preparing.jpg435 viewsMartin
Venus_3sec_freehand.jpg
Venus_3sec_freehand.jpg527 viewsVenusMartin
Dave_and_scope.jpg
Dave_and_scope.jpg532 viewsMartin

Last additions - User galleries
rosette_done_ha2Mb.jpg
rosette_done_ha2Mb.jpgRosetta in HA.512 viewsStill lots of noise in the surroundings so will need more exposures.MartinDec 28, 2014
Eta_Carinae_done_ha2Mb.jpg
Eta_Carinae_done_ha2Mb.jpgEta Carinae with the EQ8 mount.823 viewsMartinDec 28, 2014
Eta_Carina.jpg
Eta_Carina.jpgEta Carinae543 viewstest image with OAG.MartinFeb 12, 2014
Lagoondone2Mb.jpg
Lagoondone2Mb.jpgLagoon nebula680 viewsDone with the ED100 and Hutech FR/FF.MartinMay 15, 2013
triffid_done2MB.jpg
triffid_done2MB.jpgTriffid nebula747 viewsDone with the ED100 and Hutech FR/FF.MartinMay 15, 2013
testing.jpg
testing.jpgtestimage984 views2X30Seconds at ISO1600MartinMay 12, 2012
Sombrerocropdone.jpg
Sombrerocropdone.jpgSombrero galaxy1561 viewsThe Sombrero Galaxy (also known as M104 or NGC 4594) is an unbarred spiral galaxy in the constellation Virgo located 28 million light years from Earth. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk. The dark dust lane and the bulge give this galaxy the appearance of a sombrero. Astronomers initially thought that the halo was small and light, indicative of a spiral galaxy. But Spitzer found that halo around the Sombrero Galaxy is larger and more massive than previously thought, indicative of a giant elliptical galaxy. [5] The galaxy has an apparent magnitude of +9.0, making it easily visible with amateur telescopes. The large bulge, the central supermassive black hole, and the dust lane all attract the attention of professional astronomers.MartinMay 11, 2012
NGC4945.jpg
NGC4945.jpgNGC4945.1084 viewsNGC4945 with the Supernova.MartinApr 11, 2012