M41

A broad open cluster in Canis Major, lying southward of the brilliant star Sirius. M41 covers an area of the sky slightly greater than that of the Moon's disc, though it is marginally too faint to be visible without telescopic aid.

The cluster contains about a hundred stars of different shades of oranges and blues, scattered through an area some twenty-five light years in diameter. To an observer on Earth, the brightest star in the cluster is the orange giant HD 49091, which appears to lie near the cluster's centre (though in fact it lies on edge of the cluster nearest to the Solar System).

Visible on the southeastern fringes of M41 is a blue star that outshines all the others in the field, but is not in fact part of the cluster. This blue star is 12 Canis Majoris, lying in the same direction as M41 from Earth, but only about a third of the 2,400 light years' distance to M41 itself.