Observations

February 2012 night sky guide podcast, transcript and star chart

To help you learn about the southern night sky, Sydney Observatory provides an audio guide/podcast, transcript of that audio, and a sky map or chart each month. This month’s guide is presented by Melissa Hulbert, an Astronomy Educator at Sydney Observatory.

Mel provides fascinating insights into the February night sky, with her tour including the constellations Orion, Taurus, Canis Major and the former constellation of Argo Narvis (the Ship of the Argonauts) – which has since been broken up into three smaller constellations, each being a part of the ship: Carina (the keel), Vela (the sails) and Puppis (the poop).

Planets to look out for this month are Venus, Jupiter, Mars and Saturn – with the Moon close to Venus and Jupiter after sunset from 25 to 28 February, making a striking trio in our western sky.

Listen to the audio, or read the transcript below for more details.

HEAR THE AUDIO
You can subscribe with iTunes or upload the audio to your iPod or mp3 player, or listen to it on your computer.

SEE THE SKY CHART
We provide an embedded sky map (below) and a February 2012 night sky chart (PDF) which shows the stars, constellations and planets visible in the night sky from anywhere in Australia. To view PDF star charts you will need to download and install Adobe Acrobat Reader if it’s not on your computer already.

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BUY THE BOOK
Our annual book, ‘The 2012 Australasian sky guide’, by Dr Nick Lomb has more information and star maps for months from December 2011 until December 2012 inclusive, plus information about the Sun, twilight, the Moon and tides, and a host of other fascinating astronomical information. You can purchase it ($16.95) at Sydney Observatory and Powerhouse Museum shops or other good bookshops, or online through Powerhouse Publishing (additional packing/postage costs apply).

READ THE TRANSCRIPT (after the jump)

Transcript of the February 2012 monthly sky guide audio

Hello and welcome to the night sky guide for February. My name is Melissa Hulbert and I’m an Astronomy Educator at Sydney Observatory.

Before we start our night sky tour, make sure you download the February sky map from our website at www.sydneyobservatory.com.au. Click the Astronomy tab, and go to the Monthly sky guides section.

Armed with your sky map and a small torch with some red cellophane covering it, find a nice dark place away from the glare of the street lights and make sure you know your cardinal directions – that’s north, south, east and west. Remember that the Sun rises in the east, moves through the northern sky during the day and sets in the west; or a small compass will also point you in the right direction. Pick a comfortable spot either on a rug or a deck chair that you can lay back in. Wait about 5-10 minutes and allow your eyes to adapt to the darkness.

Now let’s turn towards the north. High in the northern sky is the familiar constellation of Orion, the Hunter. In Greek mythology, Orion was a hunter of great skill and boasted that he could kill all living animals. Gaea the Earth goddess was alarmed by his statement and, fearing for all the animals on Earth, she sent a scorpion to kill him. Orion was stung on the shoulder but was later revived and placed in the stars along with the scorpion. This entire myth is played out in the stars each year. As Scorpius the scorpion rises in the east, Orion sets in the west defeated. When Scorpius sets in the west the healer Ophiuchus crushes the scorpion into the Earth and revives Orion so he can rise in the east again. Orion appears in many cultures, even the ancient Egyptians saw Orion as Osiris, god of the underworld and of regeneration.

If you’re having difficulty picking out the hunter then look for ‘The Saucepan’. This is a familiar group of stars for those of us in the Southern Hemisphere and is Orion’s belt and sword. Orion is upside down for us. Below ‘The Saucepan’ you should see the red supergiant star, Betelgeuse. Remember the scorpion’s sting? Betelgeuse has a distinct reddish tinge to our eye and is the shoulder or armpit of Orion. Above ‘The Saucepan’ and diagonally opposite Betelgeuse is a brilliant white star – Rigel, one of Orion’s knees. Rigel is a blue-white supergiant star which is about 60,000 times more luminous than our own Sun. Rigel also has a small companion star which is best seen through a telescope though if seeing conditions are not the best, small telescopes will struggle to see the companion through the glare of Rigel.

Let’s return to the belt of Orion and follow its line to the west where we come to the back of a sideways ‘V’. This ‘V’ is the head of Taurus the bull who appears to be charging at Orion.

Taurus, like Orion, is also steeped in Greek mythology and represents the bull Zeus changed into to carry Princess Europa off to Crete.

Back to the ‘V’ which is part of a large open star cluster visible in binoculars called the Hyades. One of Taurus’ eyes is an orange giant star called Aldebaran which means ‘the follower’ and it too has a distinct orange tinge when viewed with the unaided eye. It follows the Pleiades, a wonderful open star cluster that can be seen with your eyes to the north-west of the ’V’. The Pleiades are known as the ‘Seven Sisters’ as seven stars are readily seen with your eyes, but away from city lights, up to 13 can be seen with the unaided eye. The whole cluster contains about 100 stars and binoculars are the best way to view this marvelous object.

Make your way back to Orion’s belt and this time, follow the line of the belt in the opposite direction, towards the east. Here we come straight to a very bright white star. This star is called Sirius and is the brightest star in either Southern or Northern Hemisphere. It is bright because it is close to us – only 8.7 light years away or about 87 million million kilometres from us (and that’s considered close).

Sirius features strongly in mythology. To the Greeks it was the canine companion of Orion, but could also be Hermes, the guide to the dead. To the ancient Egyptians, Sirius originally represented Anubis who invented embalming and funeral rites, and guided you through the underworld to your judgement and helped weigh your heart to determine your fate in the afterlife. Later Sirius represented the goddess Isis and the Egyptians initially based their calendar on Sirius’ yearly motion around the sky.

Sirius is the brightest star in the constellation of Canis Major or the Great Dog and perhaps is best known to our younger listeners as a character in the ‘Harry Potter’ books who is able to change into a large dog.

Let’s do an about-face and turn to look at the southern sky. High in the south is a bright star, in fact the 2nd brightest in our sky – Canopus. Canopus is a white supergiant star and is 313 light years away. Canopus was the helmsman of the Greek King Menelaus and rather appropriately is now used by spacecraft as a navigational guide.

Canopus is the brightest star in the constellation Carina, which represents the keel of a boat. Originally it was part of the large constellation Argo Narvis which was the Ship of the Argonauts, which Jason and the Argonauts used in their quest for the Golden Fleece. So, nearby you will see Vela the sails and Puppis the poop. In 1793 Argo Narvis was divided into the three constellations we see today.

If you are away from city lights you might make out two cloud-like shapes in the southern sky. A large one almost straight overhead in the southern sky and a smaller one a little lower and to the west. These are the clouds of Magellan, but they are not clouds. They are companion galaxies to our own Milky Way. They are gravitationally attached to our galaxy and we now know there is physical interaction between these galaxies and our own.

So what else can we look forward to seeing in the sky in February 2012?

This month after sunset, look towards the west and you will see two brilliant white star-like objects. Closest to the horizon is our sister planet, Venus. It is often referred to in this way as Venus is only approximately 600km smaller in diameter than our own Earth. The other object is the largest planet in our solar system, Jupiter. Binoculars will show you the four largest moons known as the Galilean satellites and small aperture telescopes will show one or two of the Jovian clouds belts. Venus is far less spectacular in binoculars or a telescope (it looks like a small round white disk) as it is shrouded in clouds and no details are visible. From the 25th – 28th, the Moon will join the two planets, making a striking trio in our western skies.

Turn towards the north-east and rising early evening is Mars. Mars’ distinct reddish-orange hue makes it easy to spot. As it approaches opposition next month (opposition is when a celestial body is opposite the Sun in the sky), Mars will brighten from -0.6 magnitude at month’s start to -1.2 by month’s end. While this apparition is not the best one to view Mars, some surface detail and a polar ice cap should be visible in a telescope on nights of good seeing. The Moon plays a visit to Mars on the 10th.

Staying in the north-east and rising around mid-evening is the wonderful ringed-planet, Saturn. Saturn’s lovely rings will be at their most open in December this year, but even now, wonderful views of Saturn’s impressive ring system can be seen. Depending on the telescope you are using you may even catch a glimpse of a few of Saturn’s moons including the second largest in our solar system, Titan.

February is not a great month for all you early-birds! So enjoy a sleep-in this month!

February also marks an interesting anniversary with it being 25 years since a star blew itself apart in the Large Magellanic Cloud. This star called Sanduleak became known as SN1987A and on 24th February it will be 25 years since the light from this cosmic explosion first reached us here on Earth. The star itself actually exploded about 168,000 years before, with the light taking that long to reach us. SN1987A has become the most studied star remnant in history and has provided great insights into supernovae and their remnants.

February 29th this year is also an important date with an announcement of the location of the Square Kilomtere Array. An Australia/New Zealand collaboration are in the running against Southern Africa. If we are lucky enough to host this telescope, it will be built in Western Australia and it is hoped will provide us with, among other things, information on a time called ‘the dark ages’ a period before the first stars shone in our Universe. Here in Australia we sit with our fingers crossed that our bid will be successful!

Don’t forget – in four months time on 6th June, a rare event will occur, a transit of Venus. More details about this can be found on our website, in the ‘2012 Australasian sky guide’ and in upcoming podcasts. If you miss it this time, you will have to wait until 2117.

If you have enjoyed this podcast and think you might want to regularly check out what’s in the night sky, why not purchase a copy of Sydney Observatory’s annual book, the ‘Australasian sky guide’. It not only contains detailed monthly sky guides, but is jam-packed with astronomical information including rise and set times for the Sun, Moon and planets, tides, with a detailed look at our Solar System and upcoming astronomical events. Only $16.95 from Sydney Observatory and Powerhouse Museum shops or you can purchase it online (additional costs apply).

You can also subscribe for free to our Sydney Observatory monthly sky guide podcasts through iTunes.

I leave you now with this quote from Dr Carl Sagan “Somewhere, something incredible is waiting to be known.”

Wishing you clear skies and see you next month under the stars!

This has been Melissa Hulbert from Sydney Observatory with the February monthly sky guide podcast.

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