On Wednesday evening, the Moon will pass across around 90% of the Sun above London. In 1652, an eclipse brought predictions of catastrophe and political upheaval; by 1715, Edmond Halley was mapping the path of darkness across the capital. As London prepares to look up again, we explore how the city has experienced eclipses across the centuries.
At around 6.17pm on Wednesday 12 August, something unusual will begin to happen above London. The Moon will start to move across the Sun and, over the following hour, more and more of the solar disc will disappear until maximum eclipse shortly after 7.12pm. The light should change and the temperature may noticeably fall before the Moon gradually moves away again, with the eclipse ending at around 8.06pm.
The Royal Observatory Greenwich’s guide to the eclipse describes it as the best solar eclipse visible from the UK and Ireland so far this century, and the closest we have come to a total eclipse since 1999.
It will be an astronomical event taking place hundreds of thousands of miles above us, but our experience of it will be distinctly urban. Buildings, trees, hills and the orientation of our streets will determine whether we see it at all, while London’s parks and open spaces will suddenly acquire a different significance as places from which to watch the sky.
Londoners have been looking upwards at eclipses for a very long time, although they have not always done so with the enthusiasm likely to greet Wednesday’s event.
One of the more extraordinary episodes came on 29 March 1652. England was then in the unsettled years between the execution of Charles I and the establishment of Oliver Cromwell’s Protectorate, and a forthcoming solar eclipse provided fertile ground for astrologers, pamphleteers and political speculation.
The celebrated astrologers William Lilly and Nicholas Culpeper were among those publishing predictions about what the eclipse might mean. Lilly produced Annus Tenebrosus, or The Dark Year, while Culpeper’s rather less reassuring publication was entitled Catastrophe Magnatum: or, The Fall of Monarchie. Predictions surrounding the eclipse encompassed political upheaval, disease and other misfortunes. One contemporary account claimed that London had been promised an “Egyptian darkness”. The approaching eclipse became sufficiently notorious to acquire its own ominous name: Black Monday. The Folger Shakespeare Library’s account of the Great Solar Eclipse of 1652 gives a fascinating picture of the predictions and pamphlet war surrounding it.
There was evidently enough anxiety in the capital for another contemporary publication to describe the episode as the “London-fright at the eclipse”. Yet when the great moment arrived, London experienced only a partial eclipse and remained considerably brighter than the predictions had suggested. One observer reported that there was still enough light to read indoors.
The response was wonderfully London in its speed and irreverence. Within days, an anonymous pamphlet appeared under the title Black Munday turn’d white, or, The astrologers knavery epitomized, attacking the “gross predictions” of Lilly, Culpeper and their fellow astrologers. The heavens had failed to deliver the promised catastrophe and their critics wasted little time pointing it out. The Folger’s collection of material relating to Black Monday includes several of the extraordinary contemporary pamphlets through which the argument played out.
The story is a reminder that eclipses were once much more than spectacles. An unexpected change in the Sun could be interpreted as a warning about disease, harvests, rulers or the political order itself. In a city already living through revolution and uncertainty, darkness arriving unexpectedly in daytime had an obvious symbolic power.
Just 63 years later, London experienced an eclipse that illustrates how quickly the intellectual world was changing.
On 3 May 1715, the capital lay in the path of a total solar eclipse. According to NASA’s historical calculations for eclipses visible from London, it was the only total eclipse visible from the capital between the years 1001 and 2000. The next will not occur over London until 2726.
By 1715, however, astronomer Edmond Halley was able to approach the event very differently. Drawing upon the new scientific understanding associated with Isaac Newton, Halley calculated the eclipse in advance and produced a map showing where totality was expected to pass across Britain. The map itself survives in the Royal Society’s collections, a remarkable early attempt to predict and communicate an eclipse geographically.
There were still plenty of people prepared to interpret the eclipse as an omen. One publication predicted damage to crops, scarcity of food and the danger of pestilence. Halley responded by explaining publicly that an eclipse arose from natural causes and specifically rejected the suggestion that it represented a warning against the relatively new King George I. An account of the continuing collision between eclipse science and superstition in 1715 shows how deeply older ideas about celestial omens persisted even as astronomers became increasingly capable of predicting them.
The contrast with Black Monday is striking. In 1652, London had been frightened by predictions of darkness and catastrophe. In 1715, one of Britain’s leading scientists was showing Londoners a map telling them where the darkness would fall. Eclipses had not lost their capacity to astonish people, but they were becoming something that could be calculated, mapped, observed and understood.
Wednesday’s eclipse will not bring the total darkness experienced by Londoners in 1715, but it should still be substantial. Because it takes place relatively late in the day, the Sun will also be getting lower as the event unfolds. The Royal Observatory therefore recommends finding somewhere with an unobstructed view towards the western horizon.
London’s geography matters here. Parliament Hill, Primrose Hill, Alexandra Palace, Greenwich Park and other elevated or open spaces provide the kind of long views that can be surprisingly difficult to find in a densely built city. Places that we normally value for their views across London will, for an hour or two, become places from which the city itself is almost incidental.
There is a broader point about public space here, although perhaps not one that needs overstating. London’s parks, hills, bridges and open spaces are valuable partly because they accommodate activities that nobody necessarily planned for. The same piece of grass can host football on one afternoon, a picnic the next and a group of strangers watching an eclipse a few days later. Good public space leaves room for Londoners to decide for themselves what to do with it.
Wednesday evening should provide a particularly visible example. Some people will seek out London’s famous viewpoints, while others will watch from gardens, balconies, streets, playgrounds and pub terraces. The physical experience will vary enormously across the city, but the event itself will be shared.
Perhaps this is what makes an eclipse particularly interesting in a city such as London.
At 7.12pm on an ordinary Wednesday, Londoners are doing millions of different things. Some are travelling home from work while others are starting shifts; dinners are being cooked, children put to bed, drinks ordered and trains boarded. London’s enormous population rarely experiences the city in quite the same way or at quite the same time.
An eclipse briefly cuts across those different routines, allowing someone watching from a tower block in Croydon to share essentially the same astronomical event as someone on Hampstead Heath, beside the Thames or standing outside an office after work.
Because this is a partial eclipse, London will not suddenly become completely dark. At maximum coverage, the Royal Observatory says conditions may feel more like a cloudy day or the approach of dusk or dawn, accompanied by noticeable changes in light and temperature. The effect may therefore be less theatrical than the complete darkness experienced in 1715, but there is something intriguing about seeing familiar streets and buildings under a quality of light that does not quite belong to that time of day.
The weather, of course, remains the part that nobody can predict with complete confidence. Cloud could obscure some or all of the eclipse, although changes in light levels may still be apparent. For anyone defeated either by London’s buildings or London’s weather, the Royal Observatory Greenwich will livestream the eclipse from 6.10pm with astronomers explaining what is happening.
However tempting the spectacle, nobody should look directly at the Sun without appropriate protection. This remains true throughout a partial eclipse because even a small visible part of the solar disc can cause permanent eye damage.
Ordinary sunglasses are not sufficient. The Royal Observatory recommends certified eclipse glasses, properly filtered solar telescopes or indirect methods such as a pinhole projector. There is also a pleasingly simple way to see the effect without looking upwards at all. Gaps between the leaves of trees can act as natural pinhole projectors, casting multiple tiny images of the eclipsed Sun onto the ground.
The UK Health Security Agency has published eclipse safety guidance ahead of Wednesday’s event.
The next partial eclipse visible from London arrives as soon as August 2027, although only around 45% of the Sun will then be obscured. An eclipse approaching Wednesday’s scale will require a much longer wait, while NASA’s calculations suggest London itself will not experience another total solar eclipse until 2726.
The London that watches that event is almost impossible to imagine. The London of 1652, when astrologers warned of darkness and political catastrophe, would be equally difficult for us to recognise today. Between the two sits Halley’s London of 1715, when the same phenomenon became something that could be predicted on a map and explained through science.
Wednesday’s eclipse belongs to another age again. We can follow its progress on our phones, watch it through telescopes thousands of miles away and know its timings to the minute. Yet the basic experience remains remarkably unchanged, with the Sun beginning to disappear and people stopping what they are doing to watch.
For a city usually absorbed by what is happening at street level, that seems reason enough to find a patch of open sky and look up.
