NGC 2362 is a small compact young open cluster in Canis Major that surrounds fourth magnitude star, tau Canis Majoris (τ CMa - mag. +4.37). This attractive grouping of 60 stars is packed into an area spanning just 6 arc minutes of apparent sky. The apparent magnitude of the cluster is quoted as +4.1, however this value is misleading as its significantly skewed because of the brilliance of τ CMa. The remaining members of NGC 2362 are much fainter, the brightest being of 7th magnitude.
Finding NGC 2362 is not difficult. It's located 2.75 degrees northeast of Wezen (δ CMa - mag. +1.83), the third brightest star in Canis Major. Sirius (α CMa), the brightest star in the night sky (mag. -1.46), is positioned 11 degrees northwest of NGC 2362. Tau CMa, a spectroscopic multiple system, shines with a combined light of tens of thousands times that of the Sun and is the stand out cluster member. It's bright enough to be seen with the naked eye. For comparison, the Sun at the same distance would shine at a feeble magnitude of +15.
NGC 2362 was discovered by Giovanni Batista Hodierna sometime before 1654 and then re-discovered by William Herschel on March 4, 1783. It's best seen from southern latitudes during the months of December, January and February.
Through popular 7x50 or 10x50 binoculars about a dozen member stars can be seen around tau CMa. Using averted vision and/or moving the bright star just outside the field of view increases the number of stars visible. NGC 2362 is a superb cluster for small telescope owners. An 80mm (3.1-inch) refractor shows dozens of stars of 7th magnitude or fainter. As with binoculars, switch to averted vision and the view literally blossoms with many more stars visible. Larger telescopes reveal all member stars, making for nice viewing. The cluster is listed as number 64 in the Caldwell catalogue.
Positioned 24 arc minutes north of NGC 2362 is UW Canis Majoris (29 CMa), a Beta Lyrae type eclipsing binary star. Magnitude +6.5 open cluster, NGC 2354, is located 1.25 degrees southwest of NGC 2362.
NGC 2362 Data Table
|Object Type||Open Cluster|
|RA (J2000)||07h 18m 42s|
|DEC (J2000)||-24h 57m 15s|
|Apparent Size (arc mins)||6 x 6|
|Age (years)||5 Million|
|Number of Stars||60|
|Other Name||Collinder 136|