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What’s up? Night sky for June 2011

Skywatchers with telescopes

Stargazers are gearing up for the June 16, 2011, total eclipse of the Moon.

THREE OF THE NAKED-EYE BRIGHTNESS PLANETS will be visible in the eastern sky before sunrise this month. These are Venus, Jupiter and Mars. Mercury has left the scene, having dropped down to the horizon and become lost in the glare of the Sun.

In the evening sky, Saturn is holding it’s own, shining high and bright.

The major sky event this month for Australian skywatchers, is the total eclipse of the Moon on the morning of June 16.

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.

June 2

New Moon occurs today at 7:03am Sydney time (June 1, 21:03 Universal Time). New Moon is the opposite of Full Moon, and means

June 7-8

The almost half-full Moon will be near the star Regulus (the brightest star in the constellation Leo) over these two days. On the 7th it will be to the left of Regulus, and on the 8th it will be above it.

June 9

It is First Quarter Moon today at 12:11pm Sydney time (02:11 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.

June 10

Look for the Moon to the left of the planet Saturn in tonight’s evening sky.

June 11

Tonight the Moon will appear quite close to the star Spica, the brightest star in the constellation Virgo.

June 12

Today the Moon will be at the closest point in its orbit, called perigee. The distance between the two bodies will be 367,189 kilometres.

June 13

The planet Mercury has been getting lower and lower in our morning sky, and has been lost in the glare of the Sun for a couple of weeks. Today, it reaches “superior conjunction“, which means that it is on the opposite side of the Sun from us.

June 14

Look for the almost-full Moon to the left of the planet Antares in tonight’s evening sky. Antares is a red supergiant star, 800 times the size of our Sun!

Total lunar eclipse

Don't miss the total lunar eclipse on the morning of June 16, 2011.

June 16 – total eclipse of the Moon

Full Moon occurs today at 6:14am Sydney time (June 15, 20:14 Universal Time). But the big news for today is the total eclipse of the Moon, which for Australian observers will occur in the hours before sunrise. The Moon will be in the western sky, and will gradually move into the Earth shadow and become dark, dropping lower and lower toward the horizon. During a total eclipse, the Moon takes on a reddish hue—sometimes pale, sometimes intense. This occurs because some of the Sun’s light filters through Earth’s atmosphere and is refracted onto the Moon.

For Australian observers, there’s more information on the total lunar eclipse (including timings) at the IceInSpace site.

For New Zealand observers, please see the Royal Astronomical Society of New Zealand’s site.

June 18

Low in the east before sunrise, you’ll see bright Venus below and to the left of a ruddy-coloured star. This is Aldebaran, a giant orange-coloured star about 65 light-years from Earth.

June 22

Today is the Southern Hemisphere’s midwinter solstice, which means that the Sun is at its furthest north in the sky (at 3:17am Sydney time, or June 21 at 17:17 Universal Time). This is the day when the hours of sunlight are at their minimum.

Stargazer looking at the sky

Enjoying the evening sky

June 23

It is Last Quarter Moon today at 9:48pm Sydney time (11:48 Universal Time).

June 24

Today the Moon will reach the farthest point in its orbit, apogee (the opposite of perigee), at a distance from Earth of 404,274 kilometres.

June 26

Have a look out to the east this morning, and you’ll see the crescent Moon quite near Jupiter.

June 29

Today the very thin crescent Moon will be just below the planet Mars in the pre-dawn eastern sky.

June 30

Finally, the very thin crescent Moon will appear above and to the left of the planet Venus. You can’t miss Venus – apart from the Sun and the Moon, it is the brightest object in the sky.

And finally, here’s the terrific Tanya Hill from the Melbourne Planetarium, with her Sky Notes for this month:

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.

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Comet doomsday nonsense

Artist's impression of a comet

Artist's impression of a comet. Comet C/2010 X1 (Elenin) will make a distant fly-by of Earth in October 2011.

I WAS ASKED THE OTHER NIGHT (by a caller while I was a guest on Tony Delroy’s Nightlife show on ABC radio), whether there is any truth to the rumour that Earth is going to be buzzed—perhaps even hit—by a comet later this year.

I must admit I hadn’t been keeping my eye on cometary matters lately, so I wasn’t able to give the caller a detailed reply. What I did say was that if a very close approach by a comet were on the cards, let alone a collision, I was sure I would have heard about it.

But I promised to investigate the matter and post something about it on SpaceInfo.com.au

Hunting around, it seems the caller had heard about Comet C/2010 X1 (Elenin), which was discovered on 10 December 2010.

Elenin is a long-period comet (ie. with an orbital period longer than 200 years) that is estimated to have a solid icy core, or nucleus, about 3 to 4 kilometres wide. Quite average for a comet.

As far as visibility for Earth-bound observers is concerned, there are two points that matter in a comet’s orbit—the point of its closest approach to the Sun, called perihelion, and its closest approach to Earth, called perigee.

A comet shines by light reflected from the gas and dust cloud that builds up around its icy nucleus—gas and dust that has been liberated from its frozen surface by the Sun’s heat. The point around perihelion is important, as this is where the most gas and dust can be expected to be liberated. (Technically speaking, the ice does not evaporate, which involves a liquid phase—it sublimates, which is when ice turns directly into gas.) The more gas and dust, the more reflected sunlight, and the brighter the overall comet will appear to be.

The time around perigee is important too, as being closest to Earth the comet will appear larger (and therefore brighter).

In the case of Elenin, perihelion will occur on 10 September 2011, and perigee will be reached on 16 October 2011 at a distance of about 34 million kilometres.

Is that close? No, it’s a long way away. It’s about 100 times further than the Moon, which means Elenin poses no threat to Earth at all.

So if you come across any Elenin doomsday stories on the Internet, please disregard them—they are nonsense.

South Australian amateur astronomer Ian Musgrave has a great set of Elenin questions and answers on his Astroblog site.

Story by Jonathan Nally.

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What’s up? Night sky for April 2011

Amateur astronomers using a telescope at dusk

Autumn nights are ideal for stargazer. Autumn mornings too, with some planets making a welcome return to our pre-dawn skies.

LIKE LAST MONTH, Venus is the star of the show in April, high in the eastern sky before sunrise. You can’t miss it—it is big and bold and brilliant.

Mercury makes a reappearance in the eastern morning sky from mid-month. As the April progresses, you’ll notice it rising higher and higher in the sky.

Ditto for Mars, which has been lost from view in the glare of the Sun for a while, but is making a reappearance in the morning sky this month, very low down in the east.

The largest planet in the Solar System, Jupiter, will also be low down on the eastern horizon before sunrise during April.

So that’s four planets all quite near to one another in roughly the same part of the sky! Definitely worth getting up early for.

Shifting to the evening sky, and the ringed planet Saturn will be bright and bold in the eastern sky after sunset.

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

April 1

Have a look out to the east before sunrise and you’ll see the Moon just below the planet Venus. You can’t miss Venus—apart from the Moon and the Sun, it’s the brightest thing in the sky!

April 2

Today the Moon will be at the farthest point in its orbit, called apogee, at a distance from Earth of 406,657 kilometres.

Also, you’ll notice that compared to yesterday the Moon has moved downwards in the sky and away from Venus. Now, it will be closer to the planet Mars, which is fainter than Venus and a ruddy colour.

April 3

New Moon occurs today at 11:32pm Sydney time (April 3, 14:32 Universal Time).

April 4

The planet Saturn reaches opposition today. This is a fancy way of saying that, from an Earth-bound observer’s point of view, it is in the opposite side of the sky to the Sun. In other words, if you could look down on the Solar System from above, the Sun, Earth and Saturn would be in a line, with Earth in the middle. Opposition generally is a good time to view a planet.

Stargazers with telescopes

Take the opportunity to get out and do some stargazing before the weather becomes too cold

April 7

The planet Jupiter reaches conjunction with the Sun today, which is a fancy way of saying that it is on the other side of the Sun as seen from Earth…although, being on the other side of the Sun, we can’t actually see it. You can think of conjunction as being the opposite of opposition (see April 4 above), so to speak. If you could look down on the Solar System from above, you’d see Jupiter, the Sun and the Earth in a line, with the Sun in the middle.

April 10

Today, the innermost planet, Mercury, reaches ‘inferior conjunction’. This is another kind of conjunction, again signifying that certain celestial bodies are in a line. In this case it is the Sun, Mercury and the Earth in a line, with Mercury in the middle. This makes it impossible to see the tiny planet, as it is lost in the glare of the Sun.

On certain special occasions, the tilt of Mercury’s orbit means that it can be seen crossing the face of the Sun when it is at inferior conjunction, in an event known as a transit. That’s not the case here—the next one will be in 2016.

April 11

It is First Quarter Moon today at 9:05pm Sydney time (April 11, 12:05 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.

April 14

The almost-full Moon will appear close to the star Regulus in this evening’s sky. Regulus is a large, blue star, and is the brightest star in the constellation Leo.

April 17

Today the Moon will be at the closest point in its orbit, called perigee, which is the opposite of apogee (see April 2). The distance between the two bodies today will be 358,090 kilometres.

Still on the Moon…take a look slightly below and to the left, and you’ll see a bright whitish-yellowish star. Well, that’s not a star, it’s the planet Saturn. If you have a telescope, or have a friend who has one, zero in on it and you’ll get a lovely view of its magnificent rings.

April 18

Full Moon occurs today at 11:44am Sydney time (April 18, 02:44 Universal Time). You won’t actually be able to see the Moon at that time, as it will be below the horizon. But take a look at sunset, and you’ll see that as the Sun sets in the west, the big, bright Moon will rise in the east.

April 20

Two planets get to say hello to each other this morning. In the eastern sky before sunrise, Mars and Mercury will appear close to each other. Be warned, though, that they will be very low down toward the horizon, so you’ll need a clear view if you’re to see them.

Over the next few weeks, four planets will be seen together in the morning sky. Here’s a short video from Tanya Hill, astronomer at the Melbourne Planetarium, explaining what we can expect to see:

April 21

Today will be an interesting to demonstrate to yourself how the Moon moves through the sky. If you get up in the morning while it’s still dark, take a look slightly above the Moon and you’ll see a ruddy-coloured star. That’s Antares, the brightest star in the constellation Scorpius. Remember that view. Now, go back outside later today in the mid-evening and find the Moon again, and you’ll see that the separation between the two has increased. This shows you how the Moon has trundled along a bit in its orbit throughout the day.

April 25

It is Last Quarter Moon today at 11:47pm Sydney time (14:47 Universal Time).

April 30

Today the Moon will again reach the farthest point in its orbit, apogee, at a distance from Earth of 406,038 kilometres. Take a look out to the east this morning and you’ll see the crescent Moon with Venus, Mercury, Mars and Jupiter (refer to the video above).

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 March 2011

Silhouette of people with telescopes

Saturn and Venus will be the planets to watch for when you're out stargazing in March 2011.

THIS MONTH, Venus will be visible in the eastern morning sky for quite some hours before sunrise. You won’t be able to miss it—it will be big and bright and wonderful.

Mercury will be very low down on the western horizon after sunset this month, and will be very difficult to see.

Mars has been lost in the glare of the Sun since early February, but during March will begin to make its reappearance in the eastern morning sky. It will be too low to be seen until towards the end of the month, however, at which time it will rise about an hour before the Sun.

Jupiter is about to be lost in the glare of the Sun. It is very low down in the west after sunset, and by the end of the month it will set (ie. drop below the horizon) only 15 minutes after the Sun does, making it essentially impossible to spot.

Saturn is the evening planet to see at the moment, rising roughly two hours before midnight and riding high in the northern sky throughout the night.

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

March 1

Look for the crescent Moon above and to the left of Venus in the eastern morning sky. Also, if you’re out stargazing after 10:00pm, look to the northeastern sky and you’ll see two fairly bright stars side by side. The one on the right is Spica, the brightest star in the constellation Virgo. The one on the left is actually a planet, Saturn.

Silhouette of people and telescopes

Autumn nights are good for stargazing.

March 5

New Moon occurs today at 7:46am Sydney time (March 4, 20:46 Universal Time).

March 6

Today the Moon will be at the farthest point in its orbit, called apogee, at a distance from Earth of 406,584 kilometres.

March 13

It is First Quarter Moon today at 10:45am Sydney time (March 12, 23:45 Universal Time).

March 17

The almost-full Moon will be above and to the left of Regulus, the brightest star in the constellation Leo.

March 18

In a demonstration of how it’s position changes from one night to the next, tonight the Moon will be above and to the right of Regulus.

March 20

Full Moon occurs today at 5:10am Sydney time (March 19, 18:10 Universal Time). Today also marks the Moon’s perigee, which is the opposite of apogee, ie. the point in its orbit when it is closest to the Earth. The distance between the two bodies today will be 356,578 kilometres. Apogee and perigee distances are not exactly the same from month to month, and it turns out that this month’s lunar perigee will be the closest for all of 2011.

Finally, have a look just below and to the right of the Moon and you’ll see a brightish ‘star’ with a yellow tinge—this is actually the ringed planet Saturn. If you have a telescope, or know someone who does, turn it to Saturn and marvel at the sight of its majestic rings.

People stargazing at night

All the sights described in the text can be seen with the unaided eye.

March 21

Today marks the equinox, when the Sun heads north of the equator. It is the point midway between the midpoint of summer and the midpoint of winter for those in the Southern Hemisphere.

Also, have a look just below and to the left of the Moon, and you’ll see a fairly bright star. This is Spica, the brightest star in the constellation Virgo.

March 25

The Moon will be above and to the right of red Antares, the brightest star in the constellation Scorpius.

March 26

It is Last Quarter Moon today at 11:07pm Sydney time (March 26, 12:07 Universal Time).

March 31

Look for the crescent Moon above and to the left of Venus in the eastern morning sky.

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