Watch the rare coincidence of 3 moons, last seen in 1866, on Jan 31

The moon partially covered by the Earth's shadow during a total lunar eclipse in this combination picture taken in Cape Town on Sept 28, 2015.
The moon partially covered by the Earth's shadow during a total lunar eclipse in this combination picture taken in Cape Town on Sept 28, 2015.PHOTO: REUTERS

SINGAPORE - On Jan 31, a rare astronomical event will occur: A coincidence of three moons - a lunar eclipse, a blue moon and a supermoon.

The last time the planets aligned this way was almost 152 years ago in 1866, a spokesman for the Science Centre Singapore told The Straits Times on Tuesday (Jan 16).

A lunar eclipse occurs when the moon enters the earth's shadow. The Jan 31 event will be the first lunar eclipse of the year.

The moon during a total lunar eclipse is also known as a blood moon due to the red colour it can take on.

Normally, there is only one full moon per calendar month and three full moons in a season, said the spokesman.

The full moon on Jan 31 will be the second full moon of the month and is dubbed a blue moon.

It does not appear blue, but is given the name for its rarity: It occurs once every two years and eight months.

Lastly, the full moon on Jan 31 will also be a supermoon, which occurs when a full moon coincides with the moon being the closest to earth.

The last blue moon took place on May 21, 2016, and the last total lunar eclipse that was visible in Singapore happened on April 4, 2015.

"After this year's total lunar eclipses, it will not be until three years later that we will be able to see another blood moon on May 26, 2021," said the Science Centre Singapore spokesman.

The centre is organising a viewing session from 7.30pm to 10.30pm at the Science Centre Singapore at 15, Science Centre Road, on the day itself.

After it posted details of the event on Facebook, more than 100 people have signed up for it and 879 have expressed interest.

Admission to the event is free and registration is not required. Viewing will be on a first come, first served basis.

Other than watching the lunar eclipse, there will be free live planetarium shows about the moon at the OmniTheatre at the Science Centre, at 7.30pm and 8pm.

There will be telescopes set up on site for viewing the moon and also food vendors from Street Food Circus.

Bag checks will be conducted for safety reasons and the Science Centre advised attendees to travel light for quicker entry. The centre will not be able to accommodate private telescopes.

Previous astronomy-related events have been well-received, with more than 3,000 turning up for the last eclipse-related event - a partial solar eclipse on March 9, 2016.

If it rains on that day, viewing will cease and resume if the rain stops by 9.30pm. It will end at 10.30pm, regardless.

The Science Centre has scheduled additional live planetarium shows about the moon in case of wet weather.