A sunset partial eclipse for the UK.

Graham writes ...

Sunset eclipse. Credit: James Trezza.

Welcome to this brief blog post for July 2026, which is a ‘heads-up’ about a striking astronomical event next month that will be visible from the UK – weather permitting. As many of you will have experienced, the UK is currently in an unprecedented cycle of heat waves at the moment, and we are beginning to take clear skies night and day for granted. But a three-week period between now and 12 August is a long-time in British meteorology – so we shall see?

What’s happening on 12 August? A deep partial solar eclipse will happen during the evening sunset period, hopefully giving a visually dramatic display. The picture below shows the path of totality of the eclipse – if you imagine the centre line of this band then that’s the ground track of the locations where the period of totality is a maximum. As you can see, the track is mostly over the North Atlantic but there will be lots of people on the Iberian Peninsula who will be lucky enough to see a total eclipse at sunset.

The ground track of totality for the eclipse on 12 August 2026. Credit: NASA.

For those of you who are less enthusiastic about these things, and maybe wondering what a solar eclipse is, then the diagram below shows the geometry of Sun, moon and Earth during these events. Moving on its orbit, the moon comes directly between the Sun and Earth, casting its shadow on the Earth’s surface. You can see that the shadow has two parts. Where the umbral shadow intersects the Earth’ surface gives a total eclipse – effectively the band in the map above gives the track of the umbral shadow. A larger area experiences the penumbral shadow where a partial eclipse is seen, and that encompasses the entire UK on this occasion. However, because the UK is close to the totality track, we will experience a deep partial eclipse where typically 90% of the Sun will be covered.

The geometry of Sun, moon and Earth during a solar eclipse. Credit: Encyclopeadia Britannica Inc, (c) 2014.

To be more specific I have chosen my own location, the city of Southampton, UK, to give more details. In Southampton we will see a 93% partial eclipse, but the details do not vary too much across the UK. For example, the cover at a few sample locations are Exeter 94%, Liverpool 92%, London and Ipswich 91%. And the timing of events are not dissimilar either.

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Generally, you will need a clear, unobstructed horizon in the W to NW direction – basically the sunset direction. For viewers in Southampton the eclipse will take place while the Sun drops from about 20 degrees elevation to about 3 degrees and in terms of timings we have:
 
18.18 BST       Eclipse begins
19.14 BST       Partial eclipse maximum (93%)
20.07 BST      Eclipse ends
20.32 BST      Sunset
 
WARNING: In any kind of discussion about observing a solar event it is mandatory to mention that looking at the Sun (with the unaided eye, or by any telescopic means) without proper protection will damage your eyes. You will, literally, be ‘blinded by the light!’
 
After thought? - if you are a member of a church, you might see the eclipse as a great opportunity to hold a community viewing event to meet new people, and to reflect on and delight in the awesome beauty of God’s Creation – maybe a family BBQ combined with a chance for dialogue about science and faith?
 
Whatever way you wish to celebrate this event, I wish you God’s blessings!
 
Graham Swinerd
 
Southampton, UK
July 2026