What is a lunar eclipse?
An eclipse of the Moon occurs when the Earth lies directly between the Sun and the Moon, and the Moon lies in the shadow of the Earth.
What are the different types of lunar eclipse?
For a total lunar eclipse to happen, all three bodies – the Sun, the Earth and the Moon – lie in a straight line. This means that the Moon passes through the darkest part of the Earth’s shadow - the umbra.
But a lunar eclipse isn't always 'total'. There are actually three different types of lunar eclipse.
Total lunar eclipse
During a total lunar eclipse, the Moon usually turns a deep, dark red because it is illuminated by light that has passed through the Earth's atmosphere and has been bent back towards the Moon by refraction.
Partial lunar eclipse
A partial lunar eclipse happens when the Moon passes through the Earth's penumbra (the outer region of the Earth’s shadow), and only a section of it passes through the umbra (the darkest part of the Earth’s shadow).
On this occasion only a very small section of the Moon will be covered by the umbra at maximum eclipse, though the whole northern half of the Moon will be darkened by the penumbral shadow.
Penumbral lunar eclipse
A penumbral lunar eclipse occurs when the Moon travels only through the outer, fainter part of the Earth's shadow, or 'penumbra'. This happens when the Earth moves between the Sun and Moon but the three do not form a perfectly straight line.
The penumbra causes only a slight darkening of the Moon's surface, with the Moon still exposed to some direct sunlight, so this type of eclipse is easy to miss.
When is the next lunar eclipse in the UK?
The table below shows upcoming UK lunar eclipse dates.
|Type of eclipse
|What you'll see
|25 March 2024
|Penumbral lunar eclipse
|This eclipse won't be of much interest, as with the naked eye there won't be noticeable changes to the Moon. Furthermore, the Moon will set below the horizon before maximum eclipse at 7.12am GMT.
|18 September 2024
|Partial lunar eclipse
|The Moon will enter Earth's penumbra at 1.41am BST and leave at 5.47am. The maximum of this eclipse will occur at 3.44am BST, with only 3.5% of the Moon in Earth's umbra at this point.
|14 March 2025
|Partial lunar eclipse
|During this eclipse, almost all of the Moon will be in Earth's umbra. The Moon will first move into Earth's penumbra at 3.57am GMT. The maximum of the eclipse in London will be at 6.19am, because during the eclipse's actual maximum at 6.58, the Moon will have set below the horizon. Getting to a high point with a clear western view will allow you to see more of this eclipse.
|7 September 2025
|Total lunar eclipse
|The Moon will rise above the horizon just in time for us to see this total lunar eclipse from the UK. The maximum will occur at 7.33pm BST from the UK, with the eclipse's actual maximum at 7.11pm when the Moon is below the horizon. The Moon will then gradually move out of Earth's umbra and penumbra until 9.55pm. As the Moon will be low on the horizon and quite difficult to see, find a high point with a clear view to the East to see the most of this eclipse.
How to see a lunar eclipse
See astronomer Tom Kerss's top tips for observing and photographing a lunar eclipse in the video below.
When were the last lunar eclipses in the UK?
28 October 2023 partial lunar eclipse - A partial lunar eclipse was visible throughout all of Europe, Asia, Africa, and western Australia. From the UK we only saw a small fraction of the full Moon pass into the umbra. At its maximum, which occured at 21:15, just 12% was in Earth's shadow, with 6% in the umbra.
16 May 2022 total lunar eclipse - This total lunar eclipse was visible over South America, most of North America and parts of Europe and Africa. People in the UK were able to see the lunar eclipse at totality when the entire Moon turned red. The entire eclipse lasted for more than five hours, however, observers in the UK could only see the eclipse from 2.32am – 5.10am as the Moon had set below the horizon by the end of this period.
19 November 2021 - partial lunar eclipse - This eclipse was unusually long, lasting over six hours in total from the moment the Moon entered the Earth's shadow or 'penumbra'. The very early part of the eclipse was visible in the UK, but because of the timings the Moon had set before the eclipse reached its maximum.
Image: An eclipse from a thousand sunsets © Noah Kujawski | shortlisted in Astronomy Photographer of the Year 2022
How often do lunar eclipses happen?
A lunar eclipse happens between two to five times a year, with a total lunar eclipse occurring at least two every three years.
Why doesn't a lunar eclipse happen every month?
A lunar eclipse occurs during the full moon phase but an eclipse does not happen every month, even though the lunar cycle is 29.5 days. This is because the moon’s orbit is inclined by 5˚ relative to the Earth’s orbit. This means that as it travels around the Earth it also moves up and down in its orbit.
How long does a lunar eclipse last?
Since the Earth is around four times wider than the Moon, its shadow can darken the moon for up to five hours depending on conditions. Lunar eclipses can be seen between two and five times every year – from somewhere on the Earth’s surface. Total lunar eclipses are much rarer from one particular location.
What is a supermoon?
When the moon is close to perigee, the closest point to Earth in its orbit, it makes the moon appear slightly larger than usual. This phenomenon has been dubbed a “supermoon”. Much like “blood moon” it is not an official astronomical term. A “supermoon” will appear up to 7% larger than a regular full moon.
Why is a lunar eclipse called a 'blood moon' – and are they actually red?
People sometimes refer to a lunar eclipse as a ‘blood moon’ because of the way the Moon can turn a deep coppery red colour during its eclipse.
However, the colour of the Moon during totality will depend on the global state of dust in the Earth’s atmosphere. Dust in the atmosphere blocks out the higher frequency blue light waves, but the longer wavelength of red light is able to still come through.