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What’s up? Night sky for February 2014

WHEN STARTING OUT IN STARGAZING, most people are particularly keen to spot the planets. The problem is, that, to the novice, planets and stars look pretty much alike. The best way to identify planets is to determine their locations in relation to nearby bright stars or the Moon, and then see how watch as they change their positions slightly as each night passes. The information below will help you spot planets using this method.

Except where indicated, all of the phenomena described here can be seen with the unaided eye. Dates and times are for the Australian Eastern Summer Time zone, and sky directions are from the point of view of an observer at mid latitudes in the Southern Hemisphere.

7 Feb

It is First Quarter Moon today at 6:22am Sydney time. First Quarter is a good time to look at the Moon through a telescope, as the sunlight angle means the craters and mountains are throwing nice shadows, making it easier to get that 3D effect.

8 Feb

The just-past-half Moon is the north-western sky this evening, and just above it is a group of stars called the Hyades. See if you can spot them – they’re in a triangular formation. The Hyades is an ‘open star cluster’ about 153 light years from Earth, making it the closest such cluster to our Solar System. Although you’ll probably only be able to see a handful of stars with the naked eye (assuming, of course, that you’re not standing under a streetlight), a pair of binoculars will show many more – and long-exposure photographs reveal hundreds.

Just above and to the right of the Moon is a bright orange-coloured star called Aldebaran, although astronomers classify it as a red giant. It is roughly 44 times as big as the Sun and located about 65 light-years from Earth. Think about that – if Aldebaran were at the same distance from us as the Sun, it would appear 44 times as big in the sky. Just as well it’s a long way away!

View showing where the Moon is on the night of 8 February 2014

The Moon (shown bigger than it really is) will be near the star Aldebaran and the star cluster the Hyades on the evening of 8 February. Another star cluster, the Pleiades, is lower in the sky.

11 Feb

By tonight, you’ll see that Moon has moved a fair distance to the right (or east) of the Hyades, as a result of its slow orbit around the Earth. You won’t be able to miss what looks to be a bright star just below the Moon – this is the planet Jupiter. Grab a pair of binoculars and see if you can make out some tiny pinpricks of light on either side of the planet – these are the moons discovered by Galileo; Ganymede, Europa, Io and Callisto. Try to see all four – you might find there are two on each side of Jupiter, or one and three, or all four on one side – depending on where they are in their orbits around the planet. You might find that one or more are missing – this’ll be because that moon or moons is currently hidden behind Jupiter, or in the glare in front of the planet.

View showing the position of the Moon on 11 Feb

On the evening of 10 February, the Moon (not shown to scale) will be just above the planet Jupiter.

12 Feb

Today the Moon will reach the farthest point in its orbit around Earth, apogee, at a distance of 406,231 kilometres.

15 Feb

Full Moon occurs today at 10:53am Sydney time. If you’re out stargazing tonight and look just above (or north of) the Moon, you’ll see a bright blue star. This is Regulus, the brightest star in the constellation Leo. Located about 77.5 light years from Earth, Regulus is not one star but four, grouped into two pairs – with the naked eye we see only the brightest of the four. Multiple star systems are very common throughout the Milky Way galaxy.

20 Feb

Take a look around midnight tonight and you’ll see the Moon just below what appears to be a brightish red star. This is not actually a star but the planet Mars. A small planet, it doesn’t give away much detail even when viewed through a telescope.

Just below the Moon is Spica, the brightest star in the constellation Virgo. Like Regulus, Spica is a member of a multiple star system, in this case a binary (or two) star system. The two stars orbit each other so close together that not even a telescope can show them separated. In fact, so close are they that their mutual gravitational pull distorts each of them from a round shape into an egg shape. The Spica system is about 260 light years from Earth.

View showing the position of the Moon on 20 February

If you’re up after midnight on 20 February, you’ll be greeted by the sight of the Moon with the star Spica above and the planet Mars below.

22 Feb

Tonight it’s Saturn‘s turn, with the ringed planet appearing just below and to the right of the Moon. If you have access to even a small telescope, take a look at Saturn’s amazing rings.

23 Feb

It is Last Quarter Moon today at 4:15am Sydney time. In the early hours of this morning you’ll find the star Antares above and to the right of the Moon. Antares is the brightest star in the constellation Scorpius. Like Mars, it is a red colour too – in fact, the name Antares means ‘rival of Mars’. Because they’re both in the same part of the sky, this is a good time to compare the two.

26 Feb

If you’re up before dawn, take a look out to the east and you’ll see the thin crescent Moon just above a bright ‘star’ – this is actually the planet Venus, which, aside from the Sun and the Moon, is the brightest object in the sky. Because it is in our morning sky at present, it is called the ‘morning star’. Later in the year it will be visible to west in the evening sky, and will be known as the ‘evening star’.

View showing the position of the Moon on 26 February

This shows the view out to the east less than an hour before sunrise on 26 February. The thin crescent Moon is just above the planet Venus. Very low down on the horizon, and difficult to see, is the planet Mercury. The Moon will be just to the left of Mercury on 28 February.

28 Feb

Today the Moon will be at the closest point in its orbit, called perigee, which is the opposite of apogee. The distance between the two bodies today will be 360,438 kilometres. If you’re up and about before dawn, and you have an unobstructed (by buildings, trees, hills etc) view of the eastern horizon, see if you can spot the planet Mercury just to right of the very thin crescent Moon. It won’t be easy to see either Mercury or the Moon, but give it a try.

Here are some more great sources of southern stargazing information:

Melbourne Planetarium

Royal Astronomical Society of New Zealand

If you have any questions or comments on the night sky, we’d be happy to answer them. Please use the Feedback Form below. Happy stargazing!

Images courtesy IAU.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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What’s up? The night sky for January 2014

WHEN STARTING OUT IN STARGAZING, most people are particularly keen to spot the planets, five of which are visible to the naked eye – Mercury, Venus, Mars, Jupiter and Saturn. The problem is that, to the novice, planets and stars look pretty much alike. An easy way to identify planets is to find them in relation to nearby bright stars or the Moon, and then watch as they change their positions slightly as each night passes. The information below will help you spot planets using this method.

Except where indicated, all of the phenomena described here can be seen with the unaided eye. Dates and times are for the Australian Eastern Summer Time zone, and sky directions are from the point of view of an observer at mid latitudes in the Southern Hemisphere.

People stargazing using a telescope

There’s plenty to see in the night sky during January 2014.

Jan 1

The Moon is in its ‘new’ phase (the opposite of ‘full’) tonight at 10:14pm. This means that, seen from Earth, it is in the same direction as the Sun, and therefore won’t be seen all night – which is good for stargazing, as the absence of its light will make fainter objects easier to see.

Jan 2

Today at 8:01am, the Moon will be at the closest point – called perigee – in its elliptical orbit around the Earth. The distance between the centres of the two bodies will be 356,921 kilometres.

Jan 4

Today the Earth reaches perihelion, which is the point at which our planet is closest to the Sun during its orbit. The distance separating the two bodies is 147,089,638 kilometres. Note the similarity between the words perigee and perihelion – perigee is used for anything orbiting the Earth (‘peri’ coming from the Greek for ‘around’, while the ‘gee’ part derives from gaia, the Greek word for Earth), while perihelion is used for anything orbiting the Sun (the ‘helion’ part coming from ‘Helios’, the ancient Greek god of the Sun).

There’s a common misconception that the Earth’s changing distance from the Sun (it varies from about 147 million to roughly 152 million kilometres over the course of the year) is responsible for giving us our summers and winters. This is wrong, and a few moments thought shows why. Taking perihelion as an example, the misconception says that with the Earth being at its closest point to the Sun, our planet should experience summer. Well, it’s certainly true that perihelion occurs when it is summertime in the Southern Hemisphere… but what season is it in the Northern Hemisphere? It’s winter. And why is it winter and not summer? Because perihelion has nothing to do with our seasons. The seasons are caused by the tilt of the Earth’s axis of rotation, which sees the Southern Hemisphere tilted toward the Sun at the end of the calendar year, and the Northern Hemisphere tilted away. Six months later it’s the other way around – the north is tilted toward the Sun (and thus the northern summer and southern winter are in the middle of the calendar year) and the south is tilted away.

Jan 8

It is first quarter Moon today at 2:39pm. A few days either side of first quarter is a good time to look at the Moon through a telescope, as the sunlight angle means the craters and mountains throw nice shadows, making it easier to get that 3D effect.

Jan 12

Tonight, the almost-full Moon will be just below the star Aldebaran, the brightest star in the constellation Taurus. Aldebaran is a red giant star roughly 44 times as big as the Sun, located about 65 light-years from Earth. Have a look to the left of Aldebaran and you’ll see a beautiful, broad group of stars in a V-shape. These are the Hyades. If you have a pair of binoculars, take a look; you’ll be amazed by the beautiful sight of these sparkling stars! (A little further to the left, or west, is an even more beautiful cluster of stars – the Pleiades. See the diagram for its location.)

Diagram of the night sky for January 12

The Moon will be near the star Aldebaran on the evening of January 12. Just above and to the left of Aldebaran is a group of stars called the Hyades – take a look with a pair of binoculars; it’s a beautiful sight. An even better cluster of stars, the Pleiades, is a little further to the left (or west). Below and to the right in this view is the planet Jupiter – the Moon will be close to it on January 15.

Jan 15

Tonight the almost-full Moon will be just above and to the right of what looks like a very bright star, but is in fact the planet Jupiter – the largest planet in our Solar System. If you have a decent pair of binoculars (ie. anything bigger than opera glasses), train them on Jupiter and you should be able to see its shape and perhaps even some of the ‘banding’ of the atmosphere (the planet’s different weather zones). You should also be able to see up to four tiny, bright pinpricks of light – these are the famous moons discovered by Galileo. You might see one or two on one side of Jupiter, and the others on the other side. (If you take a look in the late evening on January 18, you’ll see them all on the same side.)

Jan 16

Full Moon occurs today at 3:52pm. When the Moon is full, it rises in the east around the same time as the Sun is setting in the west, which means it will be visible all night long. This is great for finding your way around in the dark, but the Moon’s glare is generally not welcomed by stargazers as it makes fainter objects harder or impossible to see.

Still on the subject of the Moon, today at 12:54pm it will reach apogee (the opposite of perigee), which is the farthest point in its orbit around the Earth. The distance separating the centres of the two bodies will be 406,536 kilometres.

Jan 23

If you’re awake around midnight, look out to the east and you’ll see the Moon with a reddish star just below it. That ‘star’ is actually the planet Mars. Mars is a small planet, so you need at least a medium-sized backyard telescope to get any decent sort of view of it. But even as you gaze at it with the naked eye, stop and think for a moment – right now there are two missions on their way to Mars (NASA’s MAVEN and India’s Mars Orbiter), plus there are three orbiters and two operational rovers already working at or on the Red Planet. When the two new spacecraft reach their destination in September 2014, Mars is going to become a busy place!

Diagram of the evening sky for January 23

The Moon and Mars will be near each other in the sky in the early hours of January 23.

Jan 24

It is last quarter Moon today at 4:19pm. When you take a look tonight, you’ll notice that Moon has moved a bit since last night (as a result of its slow crawl around its orbit), and Mars is now above and to its left. But directly above the Moon is a bright star called Spica, which is the brightest star in the constellation Virgo. Spica is a blue giant star located about 260 light-years from Earth.

Jan 26

If you’re awake in the early hours after midnight, you’ll be rewarded with the view of the just-less-than-half Moon down near the eastern horizon, with a brightish ‘star’ just above it. That’s not a star, it’s the planet Saturn. If you have access to a small telescope, train it on Saturn and you’ll its magnificent system of rings.

Jan 29

If you’re up before the sunrise today, look out to the east and you’ll see a very thin crescent Moon. Just below it is what looks to be a very bright star, but is in fact the planet Venus. After the Sun and the Moon, Venus is the brightest object in the sky.

Diagram of the morning sky for January 29

The thin crescent Moon will be near Venus in the morning sky on January 29. (Venus is not shown to scale in this diagram.)

Jan 30

The Moon reaches perigee today, with the distance between the centres of the Earth and Moon being 357,079 kilometres.

Jan 31

New Moon occurs for the second time this month, at 8:39am

Here are some more great sources of southern stargazing information:

Melbourne Planetarium

Royal Astronomical Society of New Zealand

If you have any questions or comments on the night sky, we’d be happy to answer them. Please use the Feedback Form below. Happy stargazing!

Images courtesy IAU.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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What’s up? Night sky for February 2013

Night sky on February 3, 2013

Saturn and the Moon will appear near each other on February 3, 2013.

Except where indicated, all of the phenomena described here can be seen with the unaided eye. And unless otherwise specified, dates and times are for the Australian Eastern Standard Time zone, and sky directions are from the point of view of an observer in the Southern Hemisphere.

Feb 3

If you’re a night owl, look out to the east after midnight and you’ll see the Moon near the horizon. Below and to its right is what seems to be a bright star. It’s actually the planet Saturn. If you have access to even a small telescope, take a look. Its rings never fail to entrance. The gas giant planet has 62 confirmed natural satellites (ie. moons), and one artificial satellite – the NASA/ESA Cassini spacecraft, which has been exploring the Saturnian system since 2004. Saturn is presently about 1,455 million kilometres from Earth.

Feb 4

It is Last Quarter Moon today at 12:56am Australian Eastern Daylight Time (Feb 3, 13:56 Universal Time).

Feb 5

This evening, the Moon will appear close to the star Antares, the brightest star in the constellation Scorpius. Antares is a red supergiant star, about 880 times bigger and 10,000 times brighter than our Sun! It is about 550 light-years from Earth.

Feb 7

Today the Moon will be at the closest point in its orbit around Earth, called perigee. The distance between the two bodies will be 365,318 kilometres.

Feb 10

New Moon occurs today at 6:20pm Australian Eastern Daylight Time (07:20 Universal Time).

Feb 12

Just after sunset this evening, you might be able to see a very thin crescent Moon low on the horizon due west. To its left will be a brightish-looking ‘star’; it’s actually the planet Mercury. And just to Mercury’s left will be the ruddy-coloured planet Mars. Today Mercury is about 161 million kilometres from Earth, while Mars is about 348 million kilometres away.

Diagram showing the Moon and Jupiter

For stargazers in southern Australia, the Moon will pass in front of Jupiter on February 18, 2013.

Feb 18

There will be a major sky event this evening for those in the southern half of Australia! – the Moon will appear to move in front of the planet Jupiter. This is called an occultation (where ‘to occult’ means to ‘make go dark’). You’ll see the Moon slowly approaching Jupiter (which, to the naked eye, just looks like a bright star). Then, all of a sudden, as the Moon’s edge ‘reaches’ the planet, Jupiter will wink out. A short while later, after the Moon has moved on a bit (you’re actually watching it trundle along in its orbit), Jupiter will reappear on the other side.

Timings for the beginning of the event, in Standard (that is, non-Daylight Saving time – please adjust for your location if necessary) for capital cities are:

Adelaide: 10:00pm

Hobart: 10:22pm

Melbourne 10:33pm

Perth: 7:39pm

Unfortunately, the other capital cities will miss out.

Incidentally, it is First Quarter Moon this morning at 7:31am Australian Eastern Daylight Time (Feb 27, 20:31 Universal Time). First Quarter is a good time to look at the Moon through a telescope, as the sunlight angle means the craters and mountains are throwing nice shadows, making it easier to get that 3D effect.

Feb 19

In tonight’s evening sky, to the northwest you’ll see the Moon, and to it’s left will be a bright star. And it really is a star this time, not a planet. It’s Aldebaran, the brightest star in the constellation Taurus. Just to Aldebaran’s left, you might be able to see a wide grouping of stars (binoculars will help). This is called the Hyades star cluster.

And today the Moon is at the farthest point in its orbit around the Earth, called apogee, at a distance of 404,472 kilometres.

Feb 25

Just near the Moon in this evening’s sky, will be the star Regulus, the brightest star in the constellation Leo.

Feb 26

Full Moon occurs today at 7:26am Australian Eastern Daylight Time (Feb 25, 20:26 Universal Time).

There’s more great night sky viewing information at Melbourne Planetarium’s Skynotes site.

If you have any questions or comments on the night sky, we’d be happy to answer them. Please use the Feedback Form below. Happy stargazing!

Images courtesy IAU.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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Why was Australia lit up like Christmas tree?

Composite image of Australia at night

The apparent abundance of lights in this satellite image of Australia’s desolate outback, is easily explained – the image is made up of multiple images taken over many days and combined one on top of the other. So occasional fires or lightning bursts here and there have apparently joined up to produce large light shows in remote areas.

TWO WEEKS AGO, NASA’S Earth Observatory web site published a new map of the Earth at night, built by Earth Observatory designers together with colleagues at the US National Geophysical Data Center. That map—made possible by a new NASA and the National Oceanic and Atmospheric Administration (NOAA) satellite—showed the footprint of human civilisation on the planet, as revealed by the lights we use to brighten the darkness.

But it turns out the map showed something more. Astute readers noticed lights in areas that were thought to be uninhabited. Many of those readers pointed to Western Australia and asked: How can there be so much light there?

The image above shows the night-lights of Australia as observed by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite in April and October 2012. It is made up of multiple images that show both manmade light sources and the light of fires. The images were acquired over nine days in April 2012 and thirteen days in October 2012.

A closer view of Western Australia at night.

A closer view of Western Australia at night.

The extent of the lighting is a results of combining multiple images. Fires and other lights that were detected on one day were integrated into the composite, multi-day picture despite being temporary phenomena. Because different lands burned at different times that the satellite passed over, the cumulative result is the appearance of a massive blaze. But while the cities are fixed, the fires were temporary, moveable features.

Not every light in the night view matches up with a fire—partly because the fire map does not include fires from April and partly because not every fire leaves a scar that is detectable from space. Even simple cloud cover could prevent burn scars from being observed.

Aside from the fires, some of the night lights appearing in uninhabited areas can be attributed to natural gas flares, lightning, oil drilling or mining operations, and fishing boats—all of which can show up as points of light.

Adapted from information issued by NASA Earth Observatory. NASA Earth Observatory images by Robert Simmon, using Suomi NPP VIIRS data provided by Chris Elvidge (NOAA National Geophysical Data Center); MODIS Active Fire & Burned Area Products; and urban data from the University of Wisconsin-Madison Center for Sustainability and the Global Environment. Suomi NPP is the result of a partnership between NASA, NOAA, and the Department of Defense. Caption by Michael Carlowicz.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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What’s up? Night sky for January 2013

Except where indicated, all of the phenomena described here can be seen with the unaided eye. And unless otherwise specified, dates and times are for the Australian Eastern Daylight Time (AEDT) zone, and sky directions are from the point of view of an observer in the Southern Hemisphere.

January 2

If you’re an early riser, take a look out to the north-west and high up you’ll see a bright star near the Moon. This is Regulus, the brightest star in the constellation Leo. Actually, Regulus is not one star but four, grouped into two pairs. Multiple star systems are very common throughout the Milky Way galaxy.

The Moon will appear near the bright star Regulus on January 2.

The Moon will appear near the bright star Regulus on January 2.

And today the Earth reaches perihelion in its orbit around the Sun. Perihelion is the point in a solar orbit when the body in question (eg. Earth) is at its closest to the Sun. Perihelion occurs today at midday AEDT, at a distance between Earth and Sun of about 147,098,089 kilometres. (The opposite of perihelion is aphelion, which for Earth will occur on July 5, 2012 at a distance of about 152,097,351 kilometres.)

January 5

It is Last Quarter Moon today at 2:58pm Sydney time (03:58 Universal Time).

January 6

If you’re up very early this morning (from 2:00am onwards), you’ll see a bright star appearing to almost touch the Moon. This Spica, the brightest star in the constellation Virgo; it is a blue giant star about 260 light-years from Earth. And don’t miss tomorrow’s morning sight…

January 7

This morning, the Moon has moved along a bit in its orbit, and no longer appears to be near Spica. Instead, it appears to hover just above what appears to be another bright star, but which is instead the planet Saturn. If you have a small telescope, or can borrow someone else’s, take a look at Saturn – you’ll see the huge rings tilted nicely to our line of sight, and – depending on the power of your telescope – you might also be able to make out a couple of the planet’s moons, although they’ll only look like bright pinpricks of light.

January 7: If you're an early riser, take a look at the Moon and you'll see what appears to be bright star just below it. Well, that's actually not a star but the ringed planet Saturn.

January 7: If you’re an early riser, take a look at the Moon and you’ll see what appears to be bright star just below it. Well, that’s actually not a star but the ringed planet Saturn.

January 9

Again, the Moon has moved along in its orbit, and is now quite distant from both Spica and Saturn. This morning it appears near the red star Antares, the brightest star in the constellation Scorpius. Antares is a red supergiant star about 883 times bigger than our Sun, located about 470 light-years from us.

January 10

This morning the Moon, now a thin crescent, can be seen above what looks like a very bright star. Actually, it’s the planet Venus, low on the horizon. Venus will remain low in the east before dawn until the middle of February, when it will have moved too close to the Sun to be visible.

The Moon today will be at the closest point to Earth in its orbit, called perigee. The distance between the two bodies today will be 360,046 kilometres.

January 12

New Moon occurs today at 6:44am Sydney time (19:44 Universal Time on January 11).

January 14-27

If you have dark skies and are a little bit lucky, you might spot a few meteors between these dates, emanating from the southern sky. The Eta Carinid meteor shower occurs at this same time every year, but it’s not a very good one compared with others – you might be lucky to see a few meteors per hour, between midnight and dawn.

January 19

It is First Quarter Moon today at 10:45am Sydney time (23:45 Universal Time on January 18). First Quarter is a good time to look at the Moon through a telescope, as the sunlight angle means the craters and mountains are throwing nice shadows, making it easier to get that 3D effect.

January 21: The Moon, Jupiter and the Pleiades star cluster will all be close together in the evening sky.

January 21: The Moon, Jupiter and the Pleiades star cluster will all be close together in the evening sky.

January 21

In tonight’s evening sky, the Moon will be situated quite near a famous cluster of stars, called the Pleiades or Seven sisters. When the Moon is not around and the sky is dark, most people can make out 6 to 7 of the Pleiades stars, although eagle-eyed stargazers can see a few more. With the Moon tonight being more than half full, it might be a little harder to see them. But if you have a pair of binoculars or a small telescope, take a look and you’ll be rewarded with a lovely sight – there are actually hundreds of stars (only some of them are visible through small optical instruments) in this beautiful “open star cluster“, and it is also filled with beautiful whispy gas clouds, although the stars and the gas are not actually related to each other—we just happen to be seeing them at a time when the stars are drifting through the gas.

And what’s that bright object just to the right (east) of both the Moon and the Pleiades? That’s actually the planet Jupiter.

January 22

Today the Moon will reach the farthest point from Earth in its orbit, apogee, at a distance of 405,312 kilometres. Take a look at it, and you’ll see what looks like a bright star just above it – it’s actually the planet Jupiter, the largest planet in our Solar System. Even a pair of binoculars will begin to show its size and shape, as well as up to four of its moons. A small telescope will reveal the different cloud bands that colour its upper atmosphere.

January 27

Full Moon occurs today at 3:38pm Sydney time (04:38 Universal Time).

There’s more great night sky viewing information at Melbourne Planetarium’s Skynotes site.

If you have any questions or comments on the night sky, we’d be happy to answer them. Please use the Feedback Form below. Happy stargazing!

Images courtesy IAU.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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On top of the world

THERE HAVE BEEN MANY IMAGES of the full disc of Earth from space – a view often referred to as “the Blue Marble” – but few have looked quite like this. Using natural-colour images from the Visible/Infrared Imaging Radiometer Suite (VIIRS) on the recently launched Suomi-NPP satellite, a NASA scientist has compiled a new view showing the Arctic and high latitudes.

Earth seen from above

The view from above. Multiple satellite images have been "stitched" together to produce this view of the Northern Hemisphere of the Earth.

Ocean scientist Norman Kuring of NASA’s Goddard Space Flight Center pieced together this composite image of Europe, Asia, North Africa, and the entire Arctic. It was compiled from 15 satellite passes made by Suomi-NPP on May 26, 2012. The spacecraft circles the Earth from pole to pole at an altitude of 824 kilometres, so it takes multiple passes to gather enough data to show an entire hemisphere without gaps in the view.

Kuring stitched the image swaths together and then set up this view looking down from 70 degrees North, 60 degrees East. (That is, the view is artificial, as the satellite does not see the full disc at one time.) He was able to show the Arctic in this image because Northern Hemisphere spring spreads enough sunlight over the North Pole to allow a natural-light view.

VIIRS is a scanning radiometer that acquires data in 22 spectral bands, covering visible, near-infrared, and thermal infrared regions of the electromagnetic spectrum. It was designed to extend and improve upon the measurements of land masses, oceans, ice, and the atmosphere made over the past two decades by the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instruments.

Download a larger version of the image (689 KB, JPEG, 1500×1500 pixels)

Image by Norman Kuring, NASA/GSFC/Suomi NPP. Text adapted from information issued by Michael Carlowicz. Suomi NPP is the result of a partnership between NASA, NOAA and the US Department of Defense.

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Videos – Around the globe

HERE ARE SOME MORE fantastic short videos of Earth at night, taken by cameras aboard the International Space Station. Visible in many of them are the aurora and lightning below. Enjoy!

Adapted from information issued by NASA.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

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Earth from Space: Ouarkziz Impact Crater

Satellite image of the Ouarkziz Impact Crater

Satellite image of the Ouarkziz Impact Crater in Algeria.

THE OUARKZIZ IMPACT CRATER is located in northwestern Algeria, close to the border with Morocco. The crater was formed by a meteor impact less than 70 million years ago, during the late Cretaceous Period of the Mesozoic Era, or “Age of Dinosaurs.”

Originally called Tindouf, the 3.5-kilometre wide crater has been heavily eroded since its formation; however, its circular shape is highlighted by exposures of older sedimentary rock layers that form ridgelines trending roughly northwest to southeast. From the vantage point of an astronaut on the International Space Station, the impact crater is clearly visible with a magnifying camera lens.

A geologist interpreting this image to build a geological history of the region would conclude that the Ouarkziz crater is younger than the sedimentary rocks, as the rock layers had to be already present for the meteor to hit them. Likewise, a stream channel can be seen cutting across the centre of the crater, indicating that the channel formed after the impact had occurred. This Principal of Cross-Cutting Relationships, usually attributed to the 19th century geologist Charles Lyell, is a basic logic tool used by geologists to build relative sequence and history of events when investigating a region.

Satellite image of the Ouarkziz Impact Crater

A closer view of the Ouarkziz Impact Crater, clearly showing where a stream has broken through its rim.

Astronaut photograph provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Centre. The image was taken by the Expedition 30 crew. Text adapted from information issued by William L. Stefanov, Jacobs/ESCG at NASA-JSC.

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VIDEO: Another trip around the Earth

HERE ARE SOME MORE fantastic short videos taken by astronauts aboard the International Space Station (ISS) in Earth orbit. The ISS circles the globe every 92.5 minutes at a speed of about 27,745 kilometres per hour. This unique vantage points enables us to see the planet spinning below, with numerous countries, cities and landscapes passing underneath.

A couple of the videos show a point of view looking out the main window of the Station’s “Cupola“. The multi-window observation post attached to the side of the ISS gives astronauts and cosmonauts not only the ability to get great views of the Earth, but also to keep an eye on activities—such as spacewalks and spacecraft movements—outside the station.

Story by Jonathan Nally. Videos courtesy NASA.

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Australia from Space: Menindee Lakes

Astronaut image of Menindee Lakes

Menindee Lakes, as photographed by astronauts aboard the International Space Station.

IN THE FAR WEST of New South Wales, Australia, near the town of Menindee, a system of ephemeral, freshwater lakes are fed by the Darling River when it floods. Lake Tandou is the longest, at 18.6 kilometres from north to south. The Darling River itself was flowing in December 2011 when this image was made.

The Darling River flows southwest in tortuous fashion across the flat landscapes of this part of Australia. It has created several inland deltas in its course to the sea, with characteristic diverging channel patterns marked by younger sediments that appear greyer than the ancient red soils and rocks surrounding them.

One inland delta appears at image right, where minor channels wind across the countryside. The apex of another inland delta appears at image lower left.

Some of the Menindee Lakes have been incorporated into an artificially regulated overflow system providing for flood control, water storage for domestic use and livestock, and downstream irrigation.

The floor of Lake Tandou is used as prime agricultural land, as evidenced by its patchwork of irrigated fields that are protected from flooding. The lakes also serve as important wetlands supporting a rich diversity of birds.

Text adapted from information issued by M. Justin Wilkinson, Jacobs/ESCG at NASA-JSC. Astronaut photograph provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Centre.

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