LAST UPDATE | 13 Mar 2025

A “BLOOD MOON” will bathe a large swathe of the world in red light overnight during a rare total lunar eclipse.

And while this “Blood Moon” effect won’t be “as obvious” in Ireland as in other parts of the world, people are still encouraged to look to the sky in the early hours.

During a total lunar eclipse, the Sun, Earth and Moon line up, and the Moon enters the Earth’s shadow.

But as the Earth’s shadow creeps across the Moon, it does not entirely blot out its white glow.

Instead it turns a reddish colour as sunlight filtered through Earth’s atmosphere is refracted off the Moon’s surface.

llustration of a lunar eclipse. Alamy Stock Alamy Stock

The lunar eclipse will last around six hours.

But the period when the Moon is completely in Earth’s shadow – called the totality – will be just over an hour.

Only the most western parts of Europe will get any chance to see the totality before the Moon sets.

And of course, getting a chance to see the Moon will depend on clear skies.

The lunar eclipse will begin at 5:09am in Ireland tomorrow morning.

Astronomy Ireland says this is when the first “bite” will appear to be taken out of the Moon as it slowly slips into the Earth’s shadow, taking 76 minutes to do so.

By 6:26am, the Moon will be totally eclipsed.

David Moore, editor of Astronomy Ireland magazine, said that the totally eclipsed Moon will be low in the west as seen from Ireland, and by then, the Sun will be close to rising.

As a result, the normal “Blood Moon” effect will not be as obvious as an eclipse that occurs high in a dark sky.

However, Moore said this “shouldn’t put people off watching, as the early stages from 5am will be quite spectacular to the naked eye and will be high enough to see in a dark sky”.

“You may even see some of the ‘blood red’ effect on the eclipsed side of the Moon long before it is totally eclipsed and the morning twilight has brightened the sky,” said Moore, who added that those in the west will get a slightly better view than those on the east coast.

Moore also cautioned that it could be another four years before Ireland sees another total eclipse of the Moon, with the next one taking place on 31 December, 2028.

“This is an unusually long interval between total eclipses of the Moon,” said Moore, who added that it makes it all the more important that everyone in Ireland gets out before 7am to witness the eclipse.

Astronomy Ireland has issued a call for sightings of the eclipse to publish in its magazine. 

Meanwhile, tomorrow’s lunar eclipse is the first of two eclipses that will be visible from Ireland this month.

The second is a partial solar eclipse of the Sun on 29 March – this will be a “very deep” partial eclipse.

A partial solar eclipse occurs when the Moon passes between the Earth and the Sun, and casts a shadow on the Earth but does not fully block out the Sun.

Diagram of a Solar eclipse Alamy Stock Vector Alamy Stock Vector

Viewing even a partial solar eclipse with the naked eye is dangerous – keen skygazers are advised to use special eclipse glasses or pinhole projectors.