The blue supermoon event is not one, not two, but three hats the moon will wear across the final days of August - full moon, supermoon, and blue moon. Tonight is one of the best times to see it. 

A bluemoon - when two full moons occur in one month - is about as common as the saying would have you believe, with the last event being in 2009. 

Tonight, the bluemoon is occurring at its closest point to earth, also known as a supermoon. 

After waiting for over a decade, however, a blue moon might not be what you expect.

“It’s important to note that a blue moon is only ‘blue’ in name. It is simply a result of our calendars and timezones,” said Warrumbungles astronomer Donna Burton. 

'Donna the Astronomer' is the astronomer at Waruumbungle's Milroy Observatory. (Facebook: Milroy Observatory with Donna the Astronomer)

“There are various definitions for a blue moon. The most widely accepted is the second full moon in a month or the fourth full moon in a quarter.”

“Typically, there are 12 full moons in a year, but occasionally there are 13, leading to a blue moon occurring every two to three years,” she said. 

It’s not every two to three years, however, that it coincides as a supermoon, with another decade before another,

“It can be up to 14 per cent bigger and 30 per cent brighter than a moon at apogee, also known as a micromoon.”

Tonight, tomorrow, and if you’re lucky, Friday night, are all chances to see the blue supermoon, if conditions are clear. 

“If you want to see it at its brightest and most beautiful, I would recommend people head out tonight,” said co-owner of Coonabarabran Stargazing Branioc Rankin. 

While night time is the best chance of seeing the moon at its brightest, it will be at its most super at 11am-12pm 31 August.