Stardome astronomer Josh Aoraki said there are usually a few supermoons each year.
“The term ‘supermoon’ is more of a media term, than a scientific one,” Aoraki told RNZ.
“The scientific term for what we are describing is what’s called perigee and apogee, they are the two points where the moon is at its closest and its furthest to earth, and that’s because the moon’s orbit is elliptical. When you get the moon at its closest point during a full moon, that’s when we have a ‘supermoon’.”
According to Nasa, the full moon at its closest point can appear up to 14% bigger and 30% brighter than the faintest moon of the year, which occurs when it’s furthest from Earth in its orbit.
Nasa said the next supermoons would happen on November 5 and December 4.
When and where is best to see the supermoon?
The supermoon will look its fullest on Tuesday, but, if you happen to miss it, it will still be visible on Wednesday.
Aoraki said the best viewing time is during sunset, which will happen about 7.30pm on Tuesday.
He advises those hoping to see the supermoon to have a clear and unobstructed view of the eastern horizon as the sun is setting in the west.
“Check the forecast and get up high, if you can, if you have a nice clear view of the sky,” Aoraki said.
If weather permits it, the supermoon would be visible with the naked eye.
MetService is forecasting the weather to clear from Tuesday afternoon for most of New Zealand. However, Northland, Waikato, Bay of Plenty and Taupō are expected to be partly cloudy with the odd shower.