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Orion the Hunter

WELCOME TO the February night sky. This month belongs to the grand constellation of Orion the Hunter. This group of stars lies in the plane of the Milky Way (our galaxy) and contains many objects of interest. For example, the three stars of the belt of Orion are easily recognisable due south in the early evening. Below the belt is the star-forming region called the great Orion Nebular, which is easy to spot with a pair of binoculars when the sky is dark.

Top left in Orion is the red giant star Betelgeuse. This star is truly a giant, one million times the volume of our own star, the Sun. Betelgeuse is around 450 light-years away.

Lower right in Orion is the bright white star called Rigel. This giant star is twice as far away as Betelgeuse, at 900 light-years, and is approximately 50,000 times as bright as the Sun. The brightest nighttime star is Sirius, but Rigel is 100 times further away and 10,000 times more luminous.

By the middle of the month, it may be possible to see the elusive planet Mercury, low down on the western horizon, soon after sunset.

On the last day of the month, the very thin crescent Moon is close to Mercury in the twilight sky. On the fifth, the Moon is close to Mars and on the 11th the near full Moon is close to the ringed planet Saturn. The Moon is at first quarter on the fifth, full on February 13, last quarter on February 21 and new on February 28.

• Clive Jackson is the director of the Astronomical Observatory of Tavira (Sítio do Malhão) and the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach. Tel 281 321 754, Fax 281 324 688, e-mail [email protected] or visit www.cdepa.org