Watch as a rare blue supermoon glows above Australia's Sydney Opera House on Monday, 19 August.
A blue moon is not named after the colour and instead refers to the second full moon in one calendar month or four full moons within a season.
The moon will appear red or yellow at dusk because of the light refracting around the atmosphere at the horizon.
Today's display will be the first of four consecutive supermoons this year, according to Nasa.
A supermoon looks brighter and bigger than the regular moon as its orbit brings it closer to earth.
The moon will sit 23,000km closer to Earth than usual on Monday night.
The UK last witnessed a blue supermoon in August 2023; the next one is reportedly not until 2037.
The moon will appear full for three days, from Sunday morning through early Wednesday morning, Nasa confirmed.
