M45

From South Dublin Astronomical Society

M45
Type	Open cluster
NGC
Constellation	Taurus
Right Ascension	3h 47,
Declination	+24° 07'
Magnitude	1.6
Size	110 arc min.
Image:M45 messier image.jpg

Poised above the rooftops during late-Autumn evenings is the beautiful Pleiades star cluster. Also known as the Seven Sisters star cluster or catalogued as number 45 in Messier’s famous list, most people see the six brightest stars under a moderate sky. Binoculars show a stunning view with many steely-blue glints of light scattered across the field. At least five hundred stars are members of this swarm that lies 380 light years away. Have you ever determined just how many Pleiads you can really see with the naked eye? From a dark location you should be able to see at least ten. Many observer’s overlook the out-lying suns that are also part of the group — the whole cluster spans just under four Moon-diameters. Twenty-two stars are above magnitude 6·5 — the theoretical naked-eye limit — but in practice you won’t see that many because the glare of the brighter stars overpowers the fainter members. Check out the following website — http://www.ras.ucalgary.ca/~gibson/pleiades/