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Post Info TOPIC: Messier 48


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Messier 48

NGC 2548 (also Messier 48, M48, Collinder 17 and OCL 584) is a magnitude +5.8 open cluster located 1500 light-years away on the western border of the constellation Hydra.
The cluster comprises of at least 80 of stars (of which 50 are brighter than magnitude +13). The brightest of them are magnitude +8.8 and belongs to the A2 spectral type, and are about 70 times brightness than the Sun. M48 also contains at least 3 giant stars (spectral type GK). The age of the cluster is estimated to be 300 million years.
The best time for observation is in winter. Under favourable conditions, it can be observed with the naked eye at the southern tip of an isosceles triangle formed with a base of the stars Xi Monoceros and 2 Hydra.

The cluster was first discovered by French astronomer Charles Messier using a 100 mm (four inch) refracting telescope from Hôtel de Cluny (now the Musée national du Moyen Age), in Paris, France on the 19th February 1771; and listed as number 48 in his catalogue of comet-like objects, but then subsequently lost.
The cluster was rediscovered by Johann Bode in 1782; and by Caroline Herschel in August 1783, and listed as NGC 2548.
It was only realised in 1934 that Caroline Herschel's NGC 2548 and Charles Messier's 'missing' cluster were the same object after Oswald Thomas noticed Messier had made an four degree error in recording the declination. [an identification which became generally accepted only after T.F. Morris of the Royal Astronomical Society of Canada independently repeated it in 1959.]

Right Ascension 08h 13m 43.1s, Declination -05° 45' 02"

Owen Gingerich investigated the missing Messier Objects, concluding that M91 was probably a comet and that M102 was probably a duplication of M101. The first conclusion was later dismissed as W. C. Williams brought up evidence that M91 is probably NGC 4548, but the second is still open (M102 may be NGC 5866)

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