Australasian Science: Australia's authority on science since 1938

Star chart and guide for March 2013

By David Reneke

Your guide to the night skies this month.

Get ready to spend more time outside for stargazing fun in March. This is shaping up to be the ‘year of the comets.’ The entire astronomy community is waiting for the visit of three amazing comets to our solar system, and it starts next week!

Comet Pan-Starrs is due to pass by and should be visible in early March in the West as it swings around the Sun and re-emerges into our evening twilight. Comets are usually named after their discoverers but in this case, Pan-Starrs was named after the Panoramic Survey Telescope and Rapid Response System which was used to find the visitor.

Binoculars should easily show a bright head and swept back tail pointing away from the Sun. Mark your calendar for March 12 as there’s a special treat in store. On that date, the thin lunar crescent will join the comet for a rare photogenic pairing.

Comet LEMMON is now receding slowing away from Earth on its approach to the Sun, but should remain just above the naked eye limit for some time as it continues to approach the Sun. If we’re lucky, Lemmon may still be near the naked eye limit and visible in ordinary binoculars. Look for it around March 24.

The Moon could have some serious competition on November 29. Get ready for a fantastic sight as comet ISON approaches the Earth. This 'dirty snowball' could produce a dazzling display. Some are predicting it will burn brighter than the moon and even be visible in broad daylight!

It may prove to be brighter than any comet of the last century – it will literally knock your socks off. Comet ISON will be visible low in the east before sunrise in the week or two before closest approach and yes, it’ll be visible all around the world.

Equally as stunning and hard to miss at the moment is Venus shining brilliantly in the eastern sky just before sunrise. Venus was called the ‘goddess of love’ in Roman mythology, but we know it better as the ‘morning star’.

Jupiter is getting low in the western evening sky now and will probably catch your eye if you’re out and about just after sunset. While you’re hunting Jupiter look for comet Pan-Starrs in the same direction and try to spot its tail glistening in the fading sunlight.

Watch for Saturn rising in the east as Jupiter is setting. It’s fantastic to see the famous rings in a small telescope. They really are there, and out of all the things to see in a small telescope this is the one object with the ‘Wow’ factor.

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Autumn in Australia is great for sky gazers because we have some of the best skies in the world. There are a number of goodies in the havens this month, but now I’m going to have you seeing double. Double stars that is!

I want you to find the Southern Cross. It’s easy, just look for the shape of a ‘kite’ high up in the South Eastern sky. The distinctive shape can be seen all year round from almost anywhere in the Australia. Astronomers call it Crux, but we know it better as simply, “The Cross.”

Thousands of years ago the four stars that make up the cross were an object of worship in the Near East. It was last seen from the latitude of Jerusalem at the time of the crucifixion of Christ. Some say it foretold the event. What do you think?

Look below the cross to see the two bright pointer stars aimed directly at the Southern Cross itself. They’re in a straight line. The bottom one is Alpha Centauri, our closest star. Through a small telescope it splits in two single stars that actually orbit each other every 80 years! Try for it.

This is a real test of your eyesight and once you split the two you’ll be amazed. Alpha is a star similar to our own and may have its own solar system. Imagine, any living beings on a planet there would see two huge sunrises and sunsets every day!

There is third star in the system, a smaller one called ‘Proxima Centauri’ and it’s technically the nearest star to us, not counting our Sun. Its light takes over four years to reach us. A journey to Proxima would take a very long time, 45 million years by car, 900 million years on foot and a whopping 100,000 years by the fastest space craft! Whew!

Grab your telescope and look at the left side star of the cross. Below it you’ll find a beautiful star cluster called the Jewel Box, so named because it looks like millions of pieces of ground glass. They’re really colourful supergiant stars, reds and blues intermingled with yellows and whites in a region of sparkling light.

“Brilliant” is the word usually used to describe The Jewel Box. It’s considered one of the most beautiful sights in the night sky Stars are not scattered, they’re gathered together into vast groups known as galaxies. Ours is the Milky Way and contains about 100 billion stars. Outside that, there are hundreds of millions of other galaxies out there.

Remember stars rise about 4 minutes earlier every night, that’s about 2 hours a month. On a clear night depending on your age and your eyesight, you can see anywhere up to about 1,500 to 2,000 stars, but you can see more if you get ‘dark adapted.’ That means hanging around outside for 15 minutes and letting your eyes get accustomed to the dark.

In Australia we’re entering the March Equinox. There are two equinoxes every year, in March and September, when the sun shines directly on the equator and the length of day and night is nearly equal.

The March equinox occurs the moment the sun crosses the celestial equator, that’s the imaginary line in the sky above the Earth’s equator, from south to north. This happens early evening on March 20 this year, and it’s been doing that for almost 5 billion years.

Happy stargazing!