Lunar eclipse guide: When and where to see in the UK

The next partial lunar eclipse is on 16 July 2019. The next toal lunar eclipse is on 16 May 2022, visible from the UK in the very early hours of the morning. 

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How to see the next lunar eclipse in the UK

16 May 2022 - total lunar eclipse

On 16 May 2022 a total lunar eclipse will be visible over South America, most of North America and parts of Europe and Africa.

Those in the UK will not be able to see every part of the eclipse but will still be able to see the lunar eclipse at totality when the entire Moon turns red. The Moon will start to enter the Earth’s shadow just after 2:30am BST and the full eclipse will occur just before 4:30am. The entire eclipse lasts for more than five hours, ending at 7:50am. However, observers in the UK will only be able to see the eclipse from 2:32am – 5:10am as the Moon will have set below the horizon by the end of this period.

The optimal viewing time to see the eclipse is between 4:29am – 5:06am. This is the period of totality in London, where the Moon lies entirely in the Earth’s umbra (full shadow) appearing red and the whole of the Moon will still be visible.

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. For a total lunar eclipse to happen, all three bodies lie in a straight line. This means that the moon passes through the darkest part of the Earth’s shadow - the umbra.

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.

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.

Partial lunar eclipse

During the partial phase of the eclipse, part of the Moon travels through the Earth's full 'umbral' shadow. However, 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.

Image of glass lantern slide of a lunar eclipse taken 16 November 1910 - unknown artist 1.jpg

What time is the lunar eclipse?

The table below lists the timings for the whole eclipse as seen from London and they might differ by a few minutes for other parts of the UK.

Local time (BST) in London

Event

Direction

2:32am

Penumbral eclipse begins

The Moon will start to enter the Earth’s penumbra (area of partial shadow) and start to darken.

Low in the south west

3:27am

Partial eclipse begins

The Moon will start to enter the Earth’s umbra (area of full shadow) and leave its penumbra and will darken considerably, almost as if it is changing its phase from full moon to waning crescent in just over an hour.

Very low in the south west

4:29am

Full eclipse begins

The Moon has completely entered the Earth’s umbra and starts to turn red.

Very low in the south west

5:06am

(5:11am)

Maximum eclipse

This is when the Moon is closest to the centre of the Earth’s umbra. The maximum eclipse in London is at 5:06am as this is the point at which the entire Moon is still above the horizon at the greatest magnitude Moonset is at 5:10am. The actual maximum eclipse is at 5:11am however the Moon will be below the horizon at this time and as it sets 

Below horizon

5:53am

Full eclipse ends

The Moon will start to leave the Earth’s umbra and enter its penumbra losing its red colour.

Below horizon

6:55am

Partial eclipse ends

The Moon has left the Earth’s umbra and has completely lost its red colour. One side starts to get lighter whilst the other is still very dark as it enters the Earth’s penumbra, almost as if it is changing from a waxing crescent to a full moon in around an hour.

Below horizon

7:50am

Penumbral eclipse ends

The Moon will look slightly darker than usual and has now left the Earth’s penumbra.

Below horizon

 

Jon Culshaw is a judge for the Insight Investment Astronomy Photographer of the Year competition. Find out more

How often are lunar eclipses?

A lunar eclipse happens between two to five times a year with a total lunar eclipse occurring at least two every three years. 

16/17 July 2019 Partial lunar eclipse
10 January 2020 Penumbral lunar eclipse
5 June 2020 Penumbral lunar eclipse
5 July 2020  Penumbral lunar eclipse
16 May 2022 Total lunar eclipse 

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 are blood moons 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 – sometimes red or possible virtually invisible. Dust in the atmosphere blocks out the higher frequency blue light waves, but the longer wavelength of red light comes through.

How to photograph the lunar eclipse

See Astronomer Tom Kerss top tips for photographing a lunar eclipse

 

Photograph of A Tainted Eclipse © Phil Hart, Astronomy Photographer of the Year Our Moon Commended 2015

This article has been written by an astronomer at the Royal Observatory, Greenwich

14/08/2018: Affelia Wibisono