If you look up at the sky tonight and can't see the moon, you can probably blame the weather forecast.
But if the skies are clear and you still can't find it, don't be alarmed - it's just hiding in the Earth's shadow.
From just after 7pm the rising full moon will be in total eclipse - the first of four happening over the next year-and-a-half.
Tonight's eclipse will be the best of the bunch for Kiwi stargazers, however.
"Eclipses that occur near midnight - which are really good to look at because the moon is nice and high in the sky -are not convenient obviously, being the middle of the night," says Stardome astronomy educator David Britten.
"This eclipse occurs as the sun goes down, so it's happening at a time when people are around - they've just had dinner, children can go out and watch it."
There's just one catch though - though the time is convenient, the moon's low place in the sky won't be. When the total eclipse begins, the moon will be about 11 degrees above the horizon (90 degrees is directly overhead).
"You need to be somewhere where you have a very clear easterly view right down to the horizon," says Andrew Buckingham of the Auckland Astronomical Society (AAS).
He says to test the view, stretch your arm out with your palm perpendicular to the ground and your little finger on the horizon - where your thumb is will be about 10 degrees.
If you'd rather trust expert judgement, members of the AAS will be gathering at six locations around Auckland to watch the moon go dark: Brown's Bay Beach, Cheltenham Beach, the west end of Mission Bay, Eastern Beach, One Tree Hill and Arataki, out west.
So what can skygazers expect to see? At first, the moon will be in the penumbra - the outer edges of the Earth's shadow. But as it rises, it will enter the umbra - where Earth's shadow almost completely blocks the sun's light.
"It's only when you get to the middle part of the shadow, the umbra, that you really start seeing a crescent starting to form on the moon, and that gradually goes across and becomes darker and the crescent gets smaller and smaller," says Mr Britten.
For an hour-and-a-quarter, starting at 7:08pm, the moon will be at 'totality' - meaning it is completely enveloped within the Earth's shadow - and take on a dark-reddish hue.
"It's the same effect as the red sunset - just around the edge of the circle of the Earth, the atmosphere passes red light through and it reaches the moon, and it makes the moon look a reddish, brownish-bronze sort of colour," says Mr Britten.
But don't expect to see the 'blood moon' that has been doing the rounds on social media and email.
"The idea of it being 'blood red' is a wee bit fanciful, really - it's pretty faint. What people are going to see exactly is going to depend a lot on the local viewing conditions."
Though lunar eclipses happen far more frequently than their solar equivalents, this one comes not only at a good time for families and kids, but for astronomers.
"Jupiter is extremely bright in the evening at the moment, and Mars just came back into the evening skies - Mars is actually at its closest the day before the eclipse," says Mr Buckingham.
"Saturn's just below Mars - it'll come up about an hour-and-a-half after Mars... and the Milky Way's nice and high this time of year, so it's a pretty nice time of year to view the skies."
Mr Britten says anyone feeling burned by the failure of Comet ISON to light up the skies last year should rest assured - unlike the so-called 'comet of the century', tonight's eclipse is a foregone conclusion.
"The problems with comets is they are completely unpredictable in many ways. One that might be thought to be faint can suddenly brighten because it releases a whole bunch of stuff that you can't predict, or it could just break up like ISON did and be a fizzer from the public's point of view," he says.
"From a scientist's point of view, Comet ISON was an absolute boon. The data, the number of observations, the different telescopes and satellites that watched it, they're learning a huge amount from Comet ISON - but it just wasn't spectacular for the public to look at.
"The moon will go dark. The moon will disappear... and then it will come back. That definitely will happen."
But just how much you'll see is all dependent on the weather.
3 News
source: newshub archive
