Stargazers across a swathe of the world marvelled at a dramatic red "Blood Moon" during a rare total lunar eclipse in the early hours of Friday.

The celestial spectacle was visible in the Americas and Pacific and Atlantic oceans, as well as in the westernmost parts of Europe and Africa.

The phenomenon happens when the sun, earth and moon line up, causing our planet to cast a giant shadow across its satellite.

But as the earth's shadow crept across the moon, it did not entirely blot out its white glow. Instead the moon glowed a reddish colour.

This is because the only sunlight that reaches the moon is "bent and scattered" as it goes through earth's atmosphere, said Daniel Brown, an astronomer at Britain's Nottingham Trent University.

It is similar to how the light can become pink or red during sunrises or sunsets on earth, he added.

The more clouds and dust there are in earth's atmosphere, the redder the moon appears.

Brown called the lunar eclipse, which will last around six hours, "an amazing way to see the solar system in action."

The period when the moon is completely in earth's shadow, called the totality, lasts just over an hour.

This event has been dubbed the "Blood Worm Moon," after one of the names given to March full moons by some Native Americans.

It is the first total lunar eclipse since 2022, but there will be another one in September.

Thursday's event is a "Micromoon," meaning the moon is the farthest away it gets from earth, making it appear about seven percent smaller than normal, according to the website Earthsky.

This is the opposite of a "Supermoon," as was seen during 2022's lunar eclipse.

Some stargazers will be in for another treat later this month. That will be a partial solar eclipse. (AFP)