Extract from ABC News
The Moon will turn shades of rust and blood red tonight in the last total lunar eclipse for three years.
The eclipse will be visible right across Australia wherever there are clear skies just after moonrise.
Lunar eclipses are leisurely events, says Tanya Hill, an astronomer at Melbourne Planetarium.
"I love lunar eclipses because they happen at the same time for everybody, it's just the time zone that changes things," Dr Hill says.
Tonight's eclipse will be very leisurely, taking three hours and 40 minutes from the time it starts changing colour at 8:09pm (AEDT).
"We should get out to see this total lunar eclipse, because we won't see another one in Australia until September 8, 2025."
How much of the eclipse you'll see depends on where you live. But the good news is the Moon will be visible right across Australia when it's completely eclipsed.
Location | Time of maximum totality |
|---|---|
NSW, ACT, Victoria, Tasmania (AEDT) | 9:59pm |
Queensland (AEST) | 8:59pm |
South Australia (ACDT) | 9:29pm |
Northern Territory (ACST) | 8:29pm |
Western Australia (AWST) | 6:59pm |
During totality, the Moon will turn red (hence the nickname "blood moon"). This effect is caused by the bending of light through Earth's atmosphere.
The colour of the fully eclipsed Moon on the west coast, where it appears against a twilight sky, will look very different to the east coast.
Full details of what's happening in your state or territory are below.
What happens during a total lunar eclipse?
Total lunar eclipses happen when the Sun, Earth and Moon line up — known as syzygy — at just the right angle so the Moon passes through the Earth's shadow.
During this eclipse, the Moon is moving fairly deep into Earth's central shadow.
"The fact it's moving through quite a lot of the shadow means that the duration of the eclipse is quite long," Dr Hill says.
There are three phases during a "blood moon" eclipse: penumbral, partial and total.
The penumbral phase, which is barely perceptible, bookends the eclipse as the Moon slips through Earth's outer shadow.
The action really starts when the Moon moves across the edge of the central shadow — or umbra — when the partial phase begins.
In this phase, Earth's shadow creeps across the face of the Moon slowly, encroaching on the brightly lit area until only a thin glowing strip on the edge of the Moon remains.
The total phase begins when the glowing strip disappears and the Moon is completely in shadow.
"The Moon should turn a lovely deep reddish colour,'" Dr Hill says.
"But exactly how deep the colour goes depends on what's happening in Earth's atmosphere and how much dust is up there."
The shade of red also depends on whether the eclipse occurs during twilight or when the sky has become completely dark.
The second half of the partial phase begins when a bright light on the Moon's edge signals it's starting to slip out of the Earth's central shadow.
And in the final penumbral phase, the Moon moves back into the Earth's outer shadow.
What will I see where I live?
You'll be able to see some or all of the total phase of the eclipse from anywhere in Australia.
But not everyone will be able to see the beginning of the eclipse — it depends on where you are.
"When an eclipse occurs at moonrise, [what you see] changes from city to city," Dr Hill says.
"We can't even say it's the same for everywhere on the east coast."
Time zones aside, the Moon rises and twilight finishes earlier the further north you are. That means the Moon is higher and the sky is darker during the eclipse.
On the west coast, the Moon rises right at the point it reaches totality.
No matter where you are, the Moon will look huge as it rises above the horizon even though it's almost the furthest away in its orbit, making it technically smaller this month. The effect is due to an optical illusion that makes objects on the horizon look bigger.
You don't need anything to look at the eclipse, but if you take a pair of binoculars you may spot Uranus near the Moon during the total phase when it is dark.
Some lucky parts of Australia will even get to see the blood moon, along with the Red Planet and two red stars during totality.
Here's a rough guide to when and what you'll see across five time zones (all times are local).
NSW and ACT (AEDT)
NSW and ACT will see all of the partial and total phases of the eclipse.
"Moonrise in Sydney is an hour before the eclipse begins," Dr Hill says.
The Moon is high above the eastern horizon in the late twilight as the partial phase begins at 8.09pm.
The total phase begins at 9:16pm and reaches totality at 9:59pm against a dark sky.
Locations above Sydney will also see a red triangle just at the end of totality, made up of the red stars Aldebaran in Taurus and Betelgeuse in Orion, and Mars above the eastern horizon.
The visible eclipse (total and partial) ends at 11:49pm.
Victoria and Tasmania (AEDT)
Victoria and Tasmania see the partial and total phases of the eclipse.
The partial phase begins at 8.09pm, just 15 -16 minutes after the Moon rises in the twilight sky.
Because it's still light, especially the further south you are, it may be hard to see the colour changing on the horizon at first.
"You will kind of have this little fading out of the Moon against this colourful sky," Dr Hill says.
But the sky will be dark by the time totality begins at 9:16pm, so the Moon should turn a deep red.
Maximum eclipse is at 9:59pm.
The full visible eclipse ends at 11:49pm.
Queensland (AEST)
Queensland gets the best view of not only the eclipse, but also the red triangle during totality.
The Moon starts changing colour at 7:09pm during the partial phase more than an hour after moonrise.
Totality begins at 8:16pm and reaches its maximum point at 8:59pm.
About 10 minutes later Mars rises in the east to form a triangle below the Moon with the red stars Betelgeuse and Aldebaran.
Totality ends at 9:41pm and the partial eclipse ends at 10:49pm.
South Australia (ACDT)
South Australians will miss the first four minutes of the partial phase, which starts before moonrise.
The changing colours may be hard to see when the Moon rises in the early twilight, but as the skies get darker it should look spectacular.
"[South Australians] will see the Moon rising with just a little chunk taken out and then get to see the rest of the eclipse in its entirety," Dr Hill says.
Totality begins at 8:46pm against dark skies and reaches its maximum point at 9.29 pm.
The entire visible eclipse ends at 11:19pm.
Northern Territory (ACST)
Territorians will miss the first three minutes of the partial phase, which starts before moonrise.
The changing colours will be hard to see in the twilight, but the skies will be dark by the time totality begins at 7:46pm, bringing out the red Moon.
Totality will reach its maximum point at 8:29pm.
Totality ends at 9:11pm and the entire visible eclipse finishes at 10:19pm.
Western Australia (AWST)
Western Australia is a big state and the view is very different depending on where you live.
"The conditions in Perth are going to be quite different to more up north," Dr Hill said.
People living in the south of the state will miss the first partial phase and the first half of totality, which starts before moonrise.
But they'll make up for it when a ghostly red Moon appears just above the horizon out of the twilight skies as the eclipse peaks at 6:59pm.
"It could almost feel like there's no Moon, then all of a sudden the Moon appears high up in the sky rather than actually seeing the moon rise," Dr Hill said.
The shadow continues to slip off the Moon during twilight, but the skies will be dark for the final half hour when the second partial phase finishes at 8:49pm.
Meanwhile, people living in Broome will see the last 21 minutes of the first partial phase and all of the total phase starting at 6:16pm in the twilight.
The eclipse peaks at 6.59pm towards the end of twilight, so the Moon will appear darker further north than in Perth.
Totality ends at 7:41pm and the sky is dark as the shadow slips off the Moon.
And that's not all you'll see …
During the eclipse, the Moon will be in the constellation of Taurus the bull.
When the Moon is darker, you should be able to make out the stars around it including the beautiful Pleiades, a cluster of stars also known as the Seven Sisters.
"As the moonlight disappears during the eclipse it's like the stars and the Milky Way become brighter again," Dr Hill says.
Uranus is not visible to the naked eye, but if you have binoculars you will be able to spot it to the top right of the Moon if the skies are dark in your location during totality.
"You would only be able to see it during totality because you need the Moon's light to be blocked out," Dr Hill.
While you've got your binoculars handy, check out Jupiter above your head.
And depending upon which state you live in, Mars will be just rising in the east.
No comments:
Post a Comment