The Andromeda Galaxy M 31<\/strong><\/em> is probably the most well-known galaxy and has disappointed many observers when they were looking through their telescopes. The 12,000 light-years large central bulge appears 20 arcmin wide, corresponding to two thirds of the full Moon diameter. The entire Andromeda Galaxy spans nearly 3\u00b0 \u2013 only a few telescopes have such a large field of view. In binoculars, the 4.3m<\/sup> bright galaxy is, however, more than striking. Although no individual stars can be resolved, the elliptical shape of the galaxy, which is inclined by 15\u00b0 to the line of sight, is clearly evident, and any 10\u2009\u00d7\u200950 should be able to distinguish the central area, spiral arms and halo.<\/p>\n Under good conditions, M\u200931 is clearly visible with the naked eye. It was first mentioned in the year 902 AD in the \u201eBook of the Stars\u201c by the Arab astronomer Al Sufi as a \u201esmall cloud\u201c. Edwin Hubble revealed its true nature as a Galaxy by observing variable stars (the Cepheids) in 1923, and in 1944, Walter Baade found two different classes of stars in M\u200931, which he divided into Population I and Population II stars \u2013 this classification is still used today.<\/p>\n Just like our own Milky Way with the Magellanic Clouds, M\u200931 also has two larger companion galaxies \u2013 M\u200932 and M\u2009110. The shape of the Andromeda galaxy is clearly disturbed in the vicinity of M\u200932 by the mass of its companion galaxy. With a diameter of 150,000 light-years, M\u200931 is larger than our Milky Way. Its luminosity equals that of 73 billion Suns. The 2.5 to 3.2 million light-years distant galaxy is 3.2 times brighter than our Milky Way and even brighter than all the other members of the local group together.<\/p>\n M 32<\/strong><\/em> is a 5.2 million light-years distant satellite galaxy of M\u200931 and only 6,000 light-years across. Therefore, it appears at low magnification almost like a star, but it is easy to see in 10\u2009\u00d7\u200950 binoculars. M\u200932 is 9.1m<\/sup> bright and only seven arcmin in diameter. It is an elliptical galaxy, which contains mainly older stars, while gas and dust clouds are rare in it. M\u200932 probably has lost some of its mass to M\u200931.<\/p>\n The second companion of the Andromeda nebula is M 110<\/em><\/strong>. The only one million light-years distant galaxy appears 12 \u00d7 20 arc minutes large and is quite hard to see because it has a rather low surface brightness. Therefore it usually remains invisible in smaller devices, but at least with a 10\u2009\u00d7\u200950 it should not be too hard to find. With a diameter of 12,000 light-years, it is twice as big as M\u200932, although it has only a tenth of the extent of the Andromeda galaxy. It contains old, red stars as well as younger stars.<\/p>\n The 3,400 light-years distant open cluster NGC 752<\/em><\/strong> contains in an area with 50 minutes of arc in diameter nearly 100 stars, of which two dozen are visible in binoculars. It is located 5\u00b0 south-southwest of \u03b3 Andromedae, which is itself a pretty double star for the telescope that resembles a miniature version of Albireo in Cygnus. Its center is marked by a 7.1m<\/sup> bright star, while two stars of sixth magnitude shine in the southwest of the star cluster. However, these stars do not belong to NGC 752 \u2013 the brightest stars of the cluster only reach 8.0m<\/sup>, its overall brightness is 5.7m<\/sup>.<\/p>\n It is over a billion years old and probably originated in the peripheral regions of the Milky Way. Nowadays, it is above the galactic plane. NGC 752 shows both characteristics of an open cluster and a globular cluster.<\/p>\n The Blue Snowball NGC 7662<\/em><\/strong> is a 1,800 light-years distant planetary nebula, which appears in binoculars only as an 8.2m<\/sup> bright star. NGC 7662 requires nearly a 100x magnification to see it as a disk and its blue-green color is the best way to identify it. It is one of the brightest planetary nebulae and has an extremely hot central star \u2013 the 13.2m<\/sup> bright stellar remnant has a surface temperature of about 135,000\u00b0 F (75,000\u00b0 C).<\/p>\n","protected":false},"excerpt":{"rendered":" Andromeda is the main actress of a Greek myth cycle, which includes many of the autumn sky constellations, including Pegasus, Perseus, Cassiopeia, Cepheus and Cetus, the Whale. Its distinctive star chain, which starts at the Square of Pegasus, is easy to find. GX Andromedae is also known as Groombridge 34 and an unremarkable physical double … Andromeda<\/span> weiterlesen ![\"Wa\u0308hrend](\"http:\/\/freebook.fernglas-astronomie.de\/wp-content\/uploads\/2014\/04\/M31.jpg\")
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