January astronomy: Herefordshire and Worcestershire

by Martin Humphries Carolian Astronomy Society in Kidderminster

Happy New Year - I hope that Santa brought you that 20" telescope that you've always wanted!

A number of people have asked me if it's true that the planet "Nibiru" will crash into the Earth on the shortest day! I'd never before heard of "Nibiru", but a bit of ferreting around on the Internet produced a stack of stuff coming from a 6,000 year-old document. The "Nibiru" collision date was originally deduced to be May 2003, but as no catastrophe happened then, it has been reinterpreted as either 27 May 2012, or alternatively, as 2012's shortest day. However, the interpreters seem to have failed to understand that there are two shortest days on Earth - one in the N hemisphere in December and one in the S hemisphere in June. So which shortest day are they talking about? I'm sorry I haven't a clue, but I'm not going to lose any sleep over it - and neither should you!

Year ahead

On the contrary, 2012 is going to be a good year for stargazing. There will be two eclipses of the Sun and two of the Moon. Three meteor showers ("shooting stars") will be well placed to be seen from the UK. There are a couple of comets around at the moment, and a very rare astronomical event - a transit of Venus - will occur in June! That won't occur again until December 2117. And of course there will be the usual news and views of the stars, planets and the Moon etc.

Orion is Martin's nomination for the most beautiful of all constellation

But on to this month - there's a lot happening, so let's get on with it. Firstly, throughout this month, the Southern skies are dominated by the constellation Orion at about 22:00 UT (Universal Time - same as Greenwich Mean Time). It lies between 30 and 50° above the horizon, and is, in my opinion, the most beautiful of all the constellations, both because it really does look like a hunter with his bow and arrow, and because of the brightness of many of its stars. However, the red star Betelgeuse, which represents one of Orion's shoulders, is perhaps one of the most interesting stars in the constellation. It's a "red supergiant", already old (10 million years) for its size, and it's expected to explode anytime within the next million years - even perhaps tomorrow - which should be a very spectacular event.

The constellation Gemini is between 50 and 60° above the SE horizon, and can be picked out by its two bright stars, the white star Castor and the orange Pollux. And the constellation Taurus, the Bull, lies between 40 and 70° above the horizon, just to the W of Orion, and the deep red star Aldebaran represents Taurus' eye.

There is a major meteor shower, the Quadrantids, this month which peaks in the early hours of 4 January, with up to 80 blue and yellow meteors per hour. The Moon sets at about 04:00 UT, meaning that Moonshine will not interfere with the dark sky until the Sun rises at about 08:20.

Comets

There are two comets in the sky this month, Garradd and Levy. At the beginning of the month, Levy will be 50° above the SW horizon, half way up the Square of Pegasus, at 20:00 UT, but binoculars will be needed. By about halfway through the month, the comet will have moved to just inside the constellation Pisces, close to the bright planet Jupiter, and at the end of the month, the comet will be in the constellation Eridanus. The comet Garradd is visible with binoculars in the NE in the early hours in the constellation Hercules, towards the end of the month.

Planets

Pictures from the specially designed Cassini spacecraft

The orange/pink planet Mars is about to start a very interesting phenomenon. All the planets appear to move from E to W against the background stars during the course of time, and Mars' position can be seen to have moved every few days. But occasionally Mars appears to stop moving against the background stars and even to start moving "backwards" from W to E. This is known as "retrograde motion", and it starts on 25 January and finishes on 15 April, lasting about 82 days, until the retrograde motion ends and the planet restarts its usual E to W movement.

The very bright planet Mercury, the closest planet to the Sun, rises at about 07:00 UT at the beginning of the month, but becomes lost in the Sunrise by about 08:00. As the month progresses, Mercury becomes lower in the sky, disappearing altogether at about the middle of the month.

While you are looking at Mercury at about 07:00 UT in the morning at the beginning of the month, look also at Saturn, 30° above the S horizon, and red/orange Mars, about 40° above the SW horizon. If you have a telescope, you can see Saturn's rings beautifully displayed this month. Jupiter continues to be a bright planet in the night sky. Look about 40° above the SW horizon at 22:00 and you can't fail to see it. Finally, the planet Venus, even brighter than Jupiter, can be seen low in the SSW sky soon after Sunset.

Keep watching the skies

Martin Humphries.