A partial lunar eclipse, visible from London

Two eclipses in sixteen days is not a thing London gets often, and the second was the easier one to watch: nothing to buy, nothing to protect your eyes with, and no crowd — because it happened while the city was asleep.

The timings

The partial lunar eclipse ran in the early hours of Friday 28 August. It began at about 3.33am London time and reached maximum at about 5.12am, with roughly 93% of the Moon’s visible diameter covered by Earth’s shadow, according to the Royal Museums Greenwich.

Then it ran out of sky. Moonset was around 6.15am and the eclipse formally ended at 6.51am — by which point the Moon was already below the London horizon. The last forty minutes of it happened to somebody else.

Why it goes red

At maximum the Moon takes on a deep coppery red, the thing people call a blood moon. The cause is the Earth’s atmosphere: sunlight passing through it is scattered and bent, and the red end of that light is what carries on to the lunar surface. What you are looking at, strictly, is every sunrise and sunset on Earth projected at once onto a rock a quarter of a million miles away.

Because the Moon sat low over the south-western horizon throughout, it also read as unusually large against the skyline — the moon illusion, which is in the eye rather than the sky, but is no less convincing for it.

No glasses this time

This is the part people got wrong after August. The partial solar eclipse on 12 August filled the parks and emptied the shops of protective glasses — more than 90% of the Sun was covered, the most in UK skies since the total eclipse of 1999.

A lunar eclipse is the opposite case. Looking straight at it does no harm at all. Binoculars or a telescope are worth having, not for safety but for the surface detail.

Where to stand, when it happens again

Astronomers give one instruction: get high, with a clear view to the south-west. The difficulty in London is that most of the major parks that filled up for the solar eclipse are shut in the small hours. Hampstead Heath is open 24 hours, which makes Parliament Hill the obvious answer — height, an open southern aspect, and legally accessible at 5am.

The forecast on the day promised cloud and light rain, which is the ordinary English ending to a story like this one.