IF you look north east on a January evening the first group of stars you will notice will be Ursa Major or the Plough. Its handle will be pointing to the horizon. The North Star, Polaris, will be in its normal position due north. The ‘W’ of Cassiopeia will be high up in the north west.

The southern part of the night sky is dominated by Orion (the Hunter). Its stars are so bright that it is difficult to ignore. Look for four stars that form a giant rectangle and in the centre will be a line of three stars in a slightly tilted line. This is Orion’s Belt. The top left hand star of the rectangle is Betelgeux, which is often referred to as ‘beetle juice’! Betelgeux is a red giant star. The bottom right hand star of the rectangle is Rigel, which is a blue supergiant. This is a good chance to notice different star colours.

The colours of stars tell astronomers which ones are hotter. It may seem strange to say that blue stars, which have surface temperatures of about 30,000 degrees centigrade, are much hotter than red stars, whose surface temperatures are around 3,000 degrees centigrade.

Orion is one of our sign posts in the sky. We can use it to find our way around the winter sky. Using the three stars of Orion’s belt, draw a line down and to the left and you will reach Sirius the Dog Star, the brightest star in the constellation of Canis Major (the Great Dog) and, in fact, the brightest star in the night sky. If we use Betelgeux and draw a curved line to the left we reach Procyon the Small Dog Star, the brightest star in the constellation of Canis Minor (the Small Dog).

If we return to Orion’s belt and draw a line up and to the right we come across the bright red star Aldebaran in the constellation of Taurus (the Bull), and if we continue this line we find a cluster of stars called the Pleiades or Seven Sisters.

A line drawn from Rigel through the middle star of Orion’s Belt and through Betelgeux will lead to two bright stars, Castor and Pollux in the constellation of Gemini (The Twins). A line drawn through the right hand star of Orion’s Belt and through Bellatrix, the top right hand star of the rectangle of Orion, to the overhead point, leads to a bright yellow star called Capella in the constellation of Auriga (the Charioteer). Capella means ‘she goat’ and nearby are a small triangle of stars called ‘The Kids’.

Using Orion we are able to find all the bright stars in the winter sky, and once this has been accomplished the smaller, fainter constellations can be found.

What’s up in The Solar System?

The Planets in January

Jupiter is rising at about 10pm but it is not really clearly visible in the sky until after midnight. The other planets are all definitely morning objects. Venus the ‘Morning Star’ is still visible about an hour before sunrise; Mars is higher in the morning sky but it is not as bright and may not be so easy to find. Saturn and Mercury are still close to the Sun and are therefore difficult to find.

Meteor Showers

On the night of January 3 and 4, around 80 faint meteors per hour can be seen as we pass through the Quadrantid meteor shower. The Quadrantids are unique in that they are named after a constellation that no longer exists.

Meteors are the dusty remains left behind by a comet as it travels around the Sun. If the Earth passes through such a stream of meteor material we see a meteor shower. They are named after the constellation from which the meteors appear to come, for example, the Perseids in August appear to come from Perseus while the Geminids in December appear to come from Gemini. The Quadrantids, however, are named after the constellation Quadrans (the Quadrant), a constellation that no longer exists but is not quite forgotten due to this meteor shower.

Phases of the Moon for January

Last Quarter 2nd, New Moon 10th, First Quarter 16th, Full Moon 24th.

This month’s full moon is called the ‘After Yule Moon’, being the first full Moon after the festival of Yuletide on December 2.

On January 2, the Earth is at Perihelion, or closest point to the Sun this year, when it will be only 91¾ million miles (147 million kilometres) from the Sun.

The next meeting of the Earby Astronomical Society will be at All Saints’ Church, Earby, on Friday, January 27, from 7.30pm to 9pm. This is the Post-Christmas Party and Astro Quiz to which all are welcome.