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Canis Major

Canis Major

The constellation Canis Major lies to the south-east of Orion and contains the the brightest star in the sky, Sirius. It includes just one A-List object, the open cluster M41. This will be best seen low in the south during the winter months for northern observers but comes almost overhead for southern observers during their summer.

M41 Open Star Cluster E B M

M41 M41 (06:46:00.000 -20:46:00.00 FK5 J2000) Open (galactic) Cluster

M41 is easily found lying 4 degrees almost exactly south of Sirius so that, for northern observers, if Sirius is at the top of the field of a pair of binoculars or finder scope, M41 will be seen towards the bottom. (Southern observers: put Sirius at the bottom of the field and look towards the top.) With an overall magnitude of 4.5, it should be visible to the unaided eye under dark skies. It contains around 100 stars of which 50 are in the range 7th to 13th magnitude and so should be visible in an amateur telescope. It has a beautiful orange-red star at its heart that makes a lovely colour contrast against the backdrop of fainter stars. This is a type K3 star of magnitude 6.9 and is about 700 times more luminous than our Sun.

It is thought that M41 was observed by Aristotle in 325 BC and as such would have been the faintest object recorded in antiquity. It was added the Messier's catalogue in 1765. It lies at a distance of about 2,300 light years and its age is estimated at 190 - 200 million years.

Position: 6h 46m -20deg 44min