This is a transcript of a podcast of the June 2009 night sky guide. Download and listen to the podcast as you gaze up at the night sky.
[ intro music]
Geoffrey Wyatt: Hello, my name is Geoffrey Wyatt and I’m the Senior Astronomy Educator at Sydney Observatory, and I’m going to talk to you about what’s visible in the sky for the month of June.
Of course the sky guide and audio guide are available at our website at www.sydneyobservatory.com.au/blog. For more information about the night sky, we recommend that you purchase the ‘2009 Australian sky guide’ by Dr Nick Lomb. [Please note – the ‘2009 Australian sky guide’ has sold out since this audio was recorded; check for next year’s guide, available from November this year.]
Now the nights in June of course are pretty cool, so you’re going to need some basic equipment when you go outside to enjoy the view. You’ll need a blanket to put onto the ground so you don’t get damp.
You’ll need a blanket or some warm clothing to keep you very warm, a pillow or two, a pair of binoculars and the ‘Australian sky guide’. Now, you may also need a warm glass of Milo to keep warm or perhaps for the adults a glass or two of a fine red.
You need to be able to put yourself in a position where you’ve got a clear view of the night sky. There’s not much point sitting at the bottom of a valley trying to view the stars. It may block out some surrounding light but you lose so much of the sky. Try to get a high viewing position where you can see as much of the sky as possible.
You also need to be able to work out a couple of ways of finding your way around the night sky. There are two things that we need to be able to do. We need to be able to find the cardinal directions of north, east, south and west, and we also need to be able to measure some fairly simple angles. The easiest thing to do is, of course, wait for sunset.
Now the sun will be over the western sky – it’s not due west of course because that only happens around the time of the equinoxes, but that’s close enough for us to start with. Wait for sunset, look towards the glow and that’s roughly west. If you’re facing west, to your right will be north, to your left will be south, and directly of course behind you will be east.
We also need to be able to measure off a few simple angles because astronomers like to measure, if you like, the angle or the altitude an object has above the horizon. Clench your fists and hold them at arm’s length, and that will measure off approximately ten degrees for most adults.
Spread your fingers as wide as you can and for most adults it’s about 15 degrees. A pinky at arm’s length is about one degree or about twice the size of the full Moon.
Using our positions, our cardinal directions and our angles we should be able to navigate the sky with a fair degree of accuracy and comfort.
Now there’s something else we’re going to need. Look at the star map and you’ll see lots of points on there joined by some lines. You may have seen those fabulous traditional star maps that show elaborate drawings of lions and sea monsters and heroes like Hercules. If you expect to be able to see those in the sky, I’m afraid you’re in for a disappointment. You need imagination.
Get your five-year-old or nephew, niece, whoever, to draw a very simple stick figure or a dot-to-dot picture of a person. Look at that, and use your imagination to fill in all the missing detail.
If you do that and you’re realistic with what you’re looking for, you’ll be able to use our sky maps to help find your way and identify many of the great constellations and events that happen in the sky.
Now we’re going to start by looking west about an hour after sunset. You’ll be able to see a very bright star about two fists in altitude above the horizon. This is the brightest star in the night sky. It’s not far off setting, and it’s called Sirius, the Dog Star. It’s the brightest star in the constellation of Canis Major, the
Sirius is indeed an interesting star. Thousands of years ago, ancient Egyptians used the position of the rising Sirius against the rising Sun in something called Heliacal Rise; the minimum distance between the two that you could still see them to work out the length of the year to be 365 and a quarter days.
Do you know what? It’s taken several thousands years since them to work out the final degree of accuracy. The Egyptians, using nothing more than the Sun and Sirius, did an incredible job of calculating the length of the year.
Now you’ve also heard of Sirius by name, I would imagine from HMS Sirius, a ship in the First Fleet to come to Australia and of course the intriguing character of Sirius Black in the Harry Potter novels.
Now it takes a little bit of time and imagination but, looking at Sirius, considering him to be the chest of the side-on, simple stick figure of a dog. Now sadly his neck and his head are fairly difficult to see from Sydney, or any major city, because of the bright lights.
You can see a simple stick figure of a dog heading towards the horizon, once again, if you use your imagination.
Head to your right a little bit from Sirius, that means we’re heading towards the north-west, and you’ll see the eighth brightest star in the night sky. That’s the star Procyon, brightest star of the constellation of the Small Dog. Now sometimes imagination can only be stretched so far. You see, the Small Dog to me looks like two stars.
Join them together and you end up with a stick. Well, maybe it’s a headless, legless, tailless hot dog, I don’t know. It is in fact supposed to be the lesser of the two hunting dogs that follow their faithful master, Orion the Hunter.
Now that you’ve found Procyon or the Small Dog, what I want you to do is to continue towards the north-west, so scanning to your right
you’ll pass the very dim constellations of Gemini and the almost invisible Cancer the Crab.
You’ll come across a group of stars that looks a little bit like an upside down question mark. If you find it, what you’ve found is Leo, king of the beasts, the Lion. Of course, it is one of the zodiac constellations.
I’ve mentioned constellations before. Constellations are, simply I suppose, suburbs in the sky. We break cities and towns up into suburbs so it gives you a general idea of where they are; the location. On a clear night depending on your age and your eyesight, you can see anywhere up to about 1,500 to 2, 000 stars.
Introduce city lights and pollution, and you see less and less, sadly, but really, can anyone remember the position of 2, 000 stars? No, it’s just not possible. What people have done for thousands and thousands of years is make up memory aids.
By doing that, they’ve drawn the dot-to-dot figures to make up simple stories and pictures that go along with heroes and villains and great battles. These in effect help us navigate through the sky, because we can use the stars, the constellations to work out the time of year. And in particular, for one of them in the deep south, we can work out our direction.
Now, of the 88 constellations, some of them are ‘zodiacs’, and they do tend to be the more famous ones. ‘Zodiac’ simply means, ‘the path of the animal’. And all the zodiac constellations, bar one which I’ll talk about shortly, are living creatures. So which one isn’t? I leave you to think about that for just a few minutes because we’ll come up to it shortly over in the eastern sky.
But Leo the Lion, an upside-down question mark. Now, unfortunately it’s upside-down for us in the Southern Hemisphere, because it’s been named from the north. What I want you to do is think of a cat sitting there majestically with its legs out the front, its rear legs tucked underneath, much like the Sphinx.
So, an upside-down question mark. The chest and the fiery mane of Leo the Lion should be towards the north.
Leo was thought to represent the lions that left the desert looking for water around the time that the Nile River used to flood, which, by the way, was roughly the time that the Sun was in that particular constellation as well.
From other communities, such as the ancient Greeks, Leo was killed by Hercules as part of his Twelve Labours, and then placed into the sky. But as long as you can see the upside-down question mark you’re well on the way to seeing one of the more famous and easily recognisable zodiac constellations of the Lion.
Continue towards the north and you’ll be able to see, about two hand spans away from the tail of Leo and high above the horizon, the group of stars that looks sort of a little bit like a shopping trolley. This is of course Corvus, the Crow. Now Corvus was a fairly lazy bird that was eventually cast out into the sky by Apollo, along with Crater, the Cup and Hydra, the Snake.
But a shopping trolley? Or a bird? I can’t see both, but a shopping is far more significant to me than a bird. And who knows? As our culture evolves and changes perhaps in another thousand years, we will be talking about constellations of the shopping trolley or the mobile phone PDA.Who knows? But hopefully we will stick to the constellations that have already been around for thousands of years.
Now below the Crow and slightly to the north-east, so we’re now heading around to the east, you’ll be able to find the most magnificent constellation of all. The symbol of justice, fertility, and generally a star sign representative of the nicest people on the planet. Virgo. Just because it’s my birthday star sign has nothing to do with it, but it does lead me to an interesting point.
In fact, even though I’m a Virgo, being born in the middle of September, the sun is actually in the constellation Leo. So am I a Leo or a Virgo? This is something that people love to talk about, but perhaps it’s best left for another time.
Now I’m not really saying that Virgos are the best people on the planet. I do realise that. Our constellations are simply maps. They help us locate where the Sun, the Moon, and the planets are, especially those of the zodiac. So once again, it’s like a road map to the sky.
Sadly, the reality is that Virgo is actually a particularly dim constellation with just one bright star, and that is Spica, which represents the ear of wheat. Now to me it looks like a big spread out ‘Y’ constellation. And it represents Virgo, as I mentioned, the goddess of justice.
Now just to the east of Virgo is the only non-living zodiac. Have you figured it out yet? The next group of stars is in fact, Libra. Now Libra the Scales, according to many ancient cultures, was actually considered to be part of Scorpius. But around the time of Julius Caesar, it became known as the Scales of Justice as carried by the neighbouring constellation of Virgo.
Libra highlights also something which I really love about the stars. And that is the multicultural aspect to it. We have constellations with Greek names. We have planets with Roman names. And we have so many stars with Arabic names.
Three of the stars in Libra have the best names I think of any. The brightest star in the constellation of Libra? Zubenelgenubi, which simply means the southern claw of the scorpion. The second brightest star in Libra? Zubeneschamali, the northern claw of the scorpion. And Gamma-Librae, the third brightest star is Zubenelakrab, the scorpion’s claw.
Now look, these three stars of course do make up a fairly plain looking equilateral triangle. But, again with a bit of imagination, perhaps you can see the pair of balance scales that represent the Scales of Justice.
Coming up in the east just below Libra, is really the only zodiac constellation that really looks like its namesake. Scorpius. Oh, by the way, not Scorpio. Scorpius. You’re looking for the giant scorpion in the sky. Now what we’re going to do while we’re looking towards the east is look for the red heart of the Scorpion known as Antares, which comes from its ancient name ‘anti Ares’, or ‘rival to Mars’.
Because when Mars is quite close by, they are about the same brightness and the same colour. Antares represents the heart of the Scorpion. Now a little bit higher up from the heart, you’d be able to see three stars in a line that are perpendicular to stars at the side of Antares.
And they represent the head and, I suppose, the shortened claws of the Scorpion. Go back from the head through the line of stars to Antares, and then you’ll see a magnificent curved hook which represents the tail, leading to the sting of the Scorpion.
Now according to legend, one version has that Apollo sent the giant Scorpion after the hunter Orion, who had boasted that he could kill any animal – and by the way, who was having an affair with his sister Artemis, goddess of the hunt.
Well, later in contrition for killing her friend, Apollo helped Artemis to hang Orion’s image in the night sky. However, the Scorpion was also placed up there on the opposite side. So as Scorpius is rising in the east, Orion is just disappearing in the western sky.
Now lying near the centre of the Milky Way, Scorpius is a fabulous part of the sky to scan with a pair of binoculars. You’ll need to keep them nice and still, and the best way I think is to lie down and put a pillow on your chest and rest your arms on that and scan the sky.
You’ll be able to see some fabulous things near the tail of Scorpius and the brightest part of the Milky Way. For example, globular clusters, a collection of huge ancient stars. And a couple of open clusters. They have rather unimaginative names; M4, M6, and M7. They are pretty to look at through a pair of binoculars. So please give it a go.
Now, at this time of year, we actually get the best view of the Milky Way. And we’re quite lucky. In the Southern Hemisphere, we get the best view as well. For two reasons.
As you perhaps know, the Earth is leaning over to one side by 23- and-a-half degrees. And that tilts the Southern Hemisphere toward the centre of the galaxy.
So it passes high overhead, which means we look through the least amount of atmosphere and we see the prettiest, brightest glow, made up of billions upon billions of stars, as we look into the centre of our galaxy, just below the tail of Scorpius, some 27,000 light years away.
Now, Milky Way, where does that name come from? Via lactea. By milk. One legend has that the gods, in particular Hera, and her servants, were walking through a park or some bush, and they came across a discarded baby in the reeds. Guess who the baby turned out to be? Hercules, with enormous strength.
And as he latched onto Hera, as she nursed him for some milk, she was told that it was Hercules. The shock of Hercules’ strength and finding out who he was, she tore him from her breast, and milk squirted across the sky to become ‘via lactea’, ‘by milk’, the beautiful glow of the Milky Way.
Continue from Scorpius, around towards the south, and high in the sky you’ll be able to see the Southern Cross. This is the best time of the year to view the smallest of all 88 constellations – and by the way, the newest. It’s only officially been a constellation since 1930. It is a magnificent group of stars. It’s small and it’s bright. It actually has three of the top 30 bright stars in the sky.
Australians, as a whole, can find the Southern Cross very easily in the winter months, but they can never find it over summer. And we tend to get tricked by constellations or asterisms I should say, such as the False Cross and the Diamond Cross, which are simply stick figures, if you like, dot-to-dot figures, that aren’t constellations but they look like them.
So, in the summer, we can’t find the Southern Cross easily. But in June, the Southern Cross is placed very nicely, high in the southern sky. It looks like a traditional cross. It has the telltale Pointers to its left, or south-east if you like, which are the stars Alpha and Beta Centauri.
The Southern Cross is not only small, it’s beautiful and useful. Now, let’s say you’re outside and you’re enjoying the night sky, and you become a little bit discombobulated and you can’t find your way home. You don’t have a compass, you don’t have a mobile phone, and no one can hear you. How do you find your directions at night?
Well, throughout the year, you can use the Southern Cross. Look at the Southern Cross, and draw an imaginary line from the top of the cross through to the bottom. Extend that line, roughly four and a half times its length, and you come to a fairly empty part of the sky, actually marked off by a fairly unimaginative constellation called Octans, the Octant.
Don’t worry about looking for any stars; there are none that are very bright in this part of the sky. But what you’ve just found is the south celestial pole. This is the point in the sky around which everything in the Southern Hemisphere rotates. From that point, drop straight down to the ground, and there you have south.
Once you’ve found south, if you’re facing south, behind you is north, to your left is east, and to your right is west. Voila. The stars are beautiful, and they’re useful.
Now, the Southern Cross also has some fabulous stories behind it. To most of us, it represents a Christian cross high in the south. And that came about when Europeans started to first sail into the Southern Hemisphere and they saw what was clearly, if you like, an icon in the sky.
But what about the indigenous cultures of the southern hemisphere? Well, Maori in New Zealand know it as Te Punga, meaning the Anchor. But for a rich view of cultural interpretations, you need go no further than the Australian Aboriginal communities.
To the Kanda of the south-west of New South Wales, near the border of New South Wales and Victoria, the Southern Cross represents the four unmarried daughters of a group elder by the name of Mululu. He’s watching over them from his position of Alpha Centauri, the third-brightest star in the night sky.
But to the Anangu people of central Australia, the Southern Cross represents the footprint of a mighty eagle – the second-largest eagle in the world. The bird is known as Waluwaru. Now, sadly, I can’t pronounce it correctly, but that’s about as close as I can get. The footprint of an eagle.
So, look at it carefully. Imagine the heel leading out to three toes, if you like, one big one in the middle and one on either side, and you should be able to see the footprint of an eagle.
Now, as long as the Moon is not brightening the sky too much, and as long as you’re in a dark location, if you look carefully at the Southern Cross, immediately to your left, in June, you’ll see there’s a slightly darker patch in the Milky Way.
And this represents the nest of the eagle, where the two bright Pointer stars nearby actually represent the throwing stick used by Aboriginal communities to, well, smack the eagle in the head while they were hunting it.
Now, go back to that Coal Sack, as we call it, or the Eagle’s Nest. It’s part of a magnificent sight that only a few cultural groups identify by the lack of stars. Everything I’ve told you about so far, you look at a constellation by looking at the stars and you join the dots to make up a simple stick figure and then fill them in with your imagination.
But now we’re going to look for something which is actually the lack of stars. Apparently only two cultural groups do this, and I believe it’s some Incans in South America, and of course some Aboriginal communities in Australia.
Start off with the Eagle’s Nest. But this time, don’t consider it to be a nest, but consider it to be the head of an emu. Now, scan the bright Milky Way all the way back to Scorpius, and you’ll see there’s actually a bit of a dark dust patch or dust lane in the Milky Way. It’s not uniformly lit.
If you look carefully, you should see that from the head, which is coal sack near the Southern Cross, back toward Scorpius is a long, thin, darker dust line that suddenly widens quite dramatically. And what you’re looking at is a negative constellation, if you like, of an Emu.
And this is absolutely a magnificent sight, but you can’t see it from any town or city, and the Moon can’t be up in any part of the sky. Intriguingly, if you can visit the Ku Ring Gai Chase National Park, you’ll actually be able to see an Aboriginal stone carving, which is thought to represent the Emu in the sky.
Now, if you have a pair of binoculars, scan the Southern Cross. Look for the brightest star. At this time of year, it’s the lowest in the cross. Go in a clockwise direction – so, up to your left ever so slightly – and scan that part of the sky with a strong pair of binoculars or a small telescope.
And what you’ll be able to see is one of the most beautiful groups of stars or clusters that can ever be seen. Known by several names, one of which is not terribly exciting, NGC4755, this is also known much more romantically as the Jewel Box. The Jewel Box is a magnificent cluster of young stars just 7,800 light years away.
Light years? Have we talked about that yet? We’ll come to that quite shortly. The Jewel Box at 7,800 light years away is a beautiful group of young stars, and if you can look at it through a small telescope, you should be able to see it looks like a collection of stars in the shape of a capital letter ‘A’.
If you look very carefully you’ll see that one of the stars is red. Looking at this group of stars, you have white stars, yellow stars, bluish stars, and one red star against the lovely dark black sky. A very famous astronomer said, years and years ago, it looked like a fine piece of jewellery laid out on velvet. Ever since then, we call it the Jewel Box.
Scanning to your right, towards the south-west, along the bright part of the Milky Way, there are many beautiful clusters of stars to look at along the constellation of Carina, towards the second brightest star in the night sky, Canopus. Now, by the way, wrapped around the Southern Cross, is one of the bigger constellations in the sky.
We’ve already mentioned the two Pointers, Alpha and Beta Centauri. These represent the front feet of the half-man, half-horse of a Centaur. The Centaur, well, we’re not quite sure, but how does an idea of a half-man, half-horse come about?
There’s been suggestion that these are the result of Europeans first heading towards the east across the Silk Road and coming into contact with Chinese horsemen who, because of the stirrup, had enormous control over their horses and seemed to act in unison.
When the Europeans went back home, they told of this incredible creature which was half-man, half-horse. Chiron, by the way, was tutor to Achilles, to Heracles, and Jason of ‘Jason and the Argonauts’ fame.
As we continue around towards the south-west from the Southern Cross, near the constellation of Carina and the bright star Canopus, we can actually see what used to be the biggest constellation in the sky, Argo Navis, the ship that carried Jason and the Argonauts in search of the Golden Fleece. Unfortunately it was so big, it’s actually been broken up into four smaller constellations.
We have Vela – the Sails, Puppis – the Deck, Pyxis – the Compass, and Carina – the Keel, which contains Canopus that I’ve mentioned before. These four constellations go together to make up a magnificent ship. I think the ship is actually a bit out to sea, but you may be able to pick out a very large false cross: a much pointers.
These represent stars from Carina the Keel and Vela the Sails. It is a beautiful part of the sky to scan with a pair of binoculars.
As we head past the former constellation of Argo Navis, towards the west, we come back to where we’ve started, and we can see the bright star Sirius setting in the western sky.
Special events for June, 2009. The phases of the Moon. The full Moon will occur on Monday, the 8th of June. The full Moon is not the best time to look at the Moon. Certainly, it makes for some of the best views as the Moon rises in the east while the Sun is setting in the west, but for viewing the Moon, this is the worst time of the lunar month.
It’s pretty much like staring at a light bulb and trying to read ‘40 watts’ written on the bottom. It’s a pointless exercise. The last quarter, when the Moon rises at around midnight, occurs on Tuesday the 16th. New Moon, when the Moon is roughly between us and the Sun – so we can’t see any of it – is on Tuesday the 23rd. The first quarter Moon will be on Monday the 29th.
First quarter and the days either side are the best time to view the Moon through binoculars and a telescope because the shadows are quite long, and they accentuate the craters and the mountain ranges. It’s a, spectacular sight around the time of first quarter Moon.
The winter solstice will occur on Sunday the 21st of June at 3.46pm. This is when the Sun will reach its most northerly part of the sky and start to head back south. The time between sunrise and sunset will begin to be a little bit longer day by day.
Also on the 21st of June, at about 6am, the planet Mars will be just two pinkies away from the stunningly bright planet Venus, while a tiny sliver of the crescent Moon and the planet Mercury will be lower in the north-east in the constellation of Taurus.
You will need a very clear view towards the north-east to be able to see all of these, but it’s a spectacular sight. I really do recommend, however, that you have your printable map or your map available in the ‘Australian sky guide’.
Earlier on I mentioned the constellation of Leo the Lion, which we started off by saying looks a bit like an upside-down question mark. Find the question mark, which represents the chest and the fiery mane of the lion, and continue towards the east from that direction, and you will be able to make out the rest of the body.
As I mentioned before, it looks like a majestic cat sitting there, albeit upside down for us in the Southern Hemisphere. Near the tail, you’ll be able to see the magnificent Roman god of agriculture, a planetea, which means a ‘wandering star’, the planet Saturn. Saturn is clearly the jewel of the night sky, and along with the first quarter Moon is, probably the best thing you can ever see through a telescope.
If you have an opportunity, and we do tend to get clearer skies more often in the colder months of the year, make your way to an observatory or borrow a friend’s telescope, to look at the planet
Saturn in the constellation of Leo, and you should be able to see those magnificent rings.
On the 28th of June, the waning Moon – which means it’s getting smaller and smaller – will be fairly close to the planet Saturn, and will make for a beautiful view.
That was the monthly sky guide for the month of June, 2009, provided by Sydney Observatory. For more information, you can check our blog at www.sydneyobservatory.com.au/blog.
Don’t forget, for a more comprehensive map and details of everything, like times and positions, you can check out the ‘Australian sky guide’, available for purchase online or at the Powerhouse Museum and Sydney Observatory shops.