101 Must-See Cosmic Objects: M41

The dazzling 4.5-magnitude open star cluster M41 dangles in Canis Main some 4° south of Sirius, the brightest star within the evening sky. From a darkish website, the cluster shines to the unaided eyes as a misty glow, like a steel tag on the collar of the celestial Canine.

M41 might have been recognized by Aristotle, who described a star with a tail within the Canine — not stunning coming from a person who took a shining curiosity in comets. Right now, the cluster seems to unaided eyes precisely as he described: a round type with a dim extension to the north.

The cluster lies about 2,300 light-years distant and is 240 million years previous. There may be little intervening dust to have an effect on its look, so its 100-odd stars shine with unusual purity. At the least three of them are seventh magnitude and needs to be inside vary for sharp-eyed, naked-eye observers. Handheld binoculars will resolve a few dozen members. Roughly 50 of its stars shine between seventh and thirteenth magnitude, placing them inside attain of small- to moderate-sized telescopes.

M41’s stars will fill a telescopic discipline of view 30 % bigger than the Full Moon. Search for a placing reddish star on the coronary heart of the sprawling cluster, with streams of irregularly brilliant suns curling outward. The view is greatest at low energy. Bigger-aperture telescopes will reveal the presence of many pink (or orange) big stars; the most popular star is of spectral sort A. As much as 80 % of its stars could also be binaries. Whereas we can not see most of those, most of the cluster’s seen stars do type pairings.

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