Astronomy fans are in for a rare treat tonight, as the phenomenon known as the Blue Micro-Moon lights up the night sky.

A blue moon is the name given to the second full moon to occur in a single calendar month, a relatively rare event that typically happens only once every two or three years.

What makes this weekend’s spectacle even more unusual is that it will also be a micromoon, meaning the moon will be at one of its most distant points from Earth and appear slightly smaller in the night sky.

Blue Moon – ROBERT ATANASOVSKI/AFP via Getty Images)

This rare celestial event occurs when two full moons fall within the same calendar month, a phenomenon that happens only every two to three years.

This occurs when the Moon reaches its full phase, at the point in its orbit furthest from Earth. As a result, it will appear slightly smaller and dimmer than a typical full moon.

Astronomers say the combination of a blue moon and a micromoon is exceptionally uncommon, with the next occurrence not expected for another 27 years.