Posted by on Jan 7, 2013 in Constellation Of the Month | 0 comments

Sirius in unmistakable because of it’s brilliancy, which far exceeds that of any other star. The three members of Orion’s belt point almost directly to it. Apart from Alpha Centauri, which never rises over Britain, Sirius is the closest of the really bright stars. In reality it is not outstanding, even though it is 26 times as luminous as the sun. It has a small companion, which is not visible except with large telescopes. Sirius is known popularly as the Dog Star, and it’s glittering whiteness makes it a splendid object in binoculars.

Star Visual Magnitude Spectrum Absolute Magnitude Distance (Lt Years)
Sirius -1.43 A1 1.45 9
Adara 1.48 B2 -5.1 680
Wezea 1.85 F8 -7.1 2,100
Mirzam 1.96 var B1 -4.8 750
Aludra 2.46 B5 -7.1 2,700

M-41 Large and splashy, this fine open cluster is easily seen as a hazy patch to the naked eye, and is fully half a degree in diameter in the telescope. About 60-70 stars can be seen at low power, in many curving chains. The cluster is dominated by a bright orange star near its centre. A great open cluster.

NGC 2354 Relatively large, this open cluster is about 15-20′ in diameter, round, and composed of relatively bright stars and a sprinkling of fainter stars. The centre seems empty, with very few stars.

NGC 2359 The Thors Head Nebula. This is a large and faint diffuse nebula, which is best seen at low powers. It is about 10′ in extent, and is composed of an arching segment intersected at almost right angles by a straighter component. It is best seen with an Orion Ultra block filter, while the Lumicon UHC filter did not do as well. This is a good object for you light bucket owners.

NGC 2362 A small but very pretty open cluster surrounding the star Tau CMa. It is about 6′ in diameter, compact, and well concentrated. It has about 40 stars with most of them being moderate in brightness.

NGC 2360 This is a large open cluster, 12-15′ in diameter, with about 75 stars well concentrated to the centre. It is visible in the viewfinder and impressive through the telescope.

ADS 5951 Is a double star, this is a fine pair composed of yellow-orange and blue stars. It reminds me of a fainter version of the more famous Albireo. It’s easily split, So have a look !