It's coming: The 'super blue blood moon eclipse'

The year's first super moon, rising over Auckland's Sky Tower last Tuesday. Photo / Greg Bowker

Last week saw the "wolf moon".

Next up is the "super blue blood moon eclipse".

The last in a trilogy of "supermoons" over past weeks is due in our night skies in the early hours of February 1.

And the finale will itself be a combination of three separate but simultaneous celestial events, the first time such a phenomenon has happened since March 1866.

The first of these events is a supermoon, the second of 2018.

The term supermoon refers to when a full moon coincides with the closest the moon gets to Earth during its orbit.

During a supermoon, the moon appears about 14 per cent larger than a normal full moon and around 30 per cent brighter.

In reality, this isn't actually a drastic difference.

However, when a supermoon is close to the horizon, it appears even bigger.

Our eyes visually compare the size of earthly things, such as buildings and trees, to the size of the moon, resulting in a strikingly beautiful view.

The second celestial event to occur on this same night is a "blue moon".

This term is used when two full moons occur in a single calendar month.

Despite the phrase "once in a blue moon" meaning something occurring infrequently, an actual blue moon occurs about every two and a half years.

This phenomenon happens due to the slight differences between calendar months and lunar phases.

Each full moon occurs every 29.5 days, however calendar months vary between 28 and 31 days.

The third celestial phenomena to occur is a total lunar eclipse, also known as a blood moon.

This happens when a full moon, Earth and the Sun line up.

This alignment term is delightfully called a "syzygy" which comes from the Greek word for "being paired together."

The moon does not have its own light, but instead is illuminated due to its surface reflecting the Sun's rays.

During a total lunar eclipse, Earth blocks any direct sunlight from reaching the moon.

The Sun is behind Earth, so it causes Earth's shadow to reflect on the moon instead of the Sun's rays.

The term "blood moon" relates to light and atmosphere.

Our sky is blue because when the Sun's light hits our atmosphere, it scatters more blue light across the sky than the other colours.

Red light is often seen during sunset, because we view it through the thicker parts of Earth's atmosphere.

When the moon goes into Earth's shadow, the sunlight is passing though Earth's atmosphere and refracting onto the Moon, creating a blood-red colour across the lunar surface.

Unlike solar eclipses, lunar eclipses are completely fine to view with the naked eye.

To celebrate the event, Auckland's Stardome is hosting a "Special Sighting" event, staying open until 3am on Thursday, February, 1.

People attending can catch a planetarium show about the moon, watch live streams, look through the Zeiss telescope, peer through courtyard telescopes, take part in moon astrophotography workshops and wander through the observatory's special Lunar Exhibition.