A once-in-a-blue-moon moment will hit Kiwi skies this weekend as a blue moon and micromoon light up the night on the same evening.
It’s the kind of pairing skywatchers don’t get often – the next blue moon won’t rise until December 31, 2028.
A blue moon is the second full moon to fall in a single calendar month – our last full moon was on May 2.
The “micromoon” is the second half of the act. It means the full moon will appear while the moon is near its furthest point from Earth – so it will appear smaller in the night sky.
Te Whatu Stardome astronomer Josh Aoraki told the Heraldthe moon won’t actually turn blue – it will rise full, golden and worth a look, if the clouds don’t get in the way.
“To the untrained eye, you’re not really going to notice a difference,” Aoraki said, referring to the micromoon’s size.
However, the full moon will be impressive to see.
“They occur when the sun is setting as the moon’s rising, and you get a really beautiful colour, regardless of how bright or big the moon looks in the sky,” he said.
Kiwis won’t need a telescope to see the spectacle – though binoculars and telescopes would sharpen the view of the moon’s craters.
The trick is to find a clear patch of sky away from city lights and a look to the east after moonrise.
The moon will reach peak fullness about 8.46pm on Sunday.
Astronomers estimate a micromoon appears about 6% smaller than an average full moon – a gap slight enough that you’d really only pick it in a side-by-side photo.
There are actually two flavours of blue moon: a calendar blue moon – the second full moon in a single month – and a seasonal one: the third full moon in a season that has four.
Sunday’s is the calendar kind – a quirk of the lunar cycle never quite lining up with our 12-month calendar, which serves up an extra full moon every couple of years.
There is a catch, though – downpours and clouds are expected in many places tomorrow so choose your lookout point wisely.
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