A partial lunar eclipse is expected to be visible across the United Kingdom on 28 August, and observers may see sections of the Moon take on a reddish hue as Earth's shadow passes over it.
Unlike a total lunar eclipse, when the entire lunar disc moves into the darkest part of Earth's shadow, a partial eclipse covers only a portion of the Moon. That means any red colouring is likely to affect only the eclipsed section and may be more subtle than in a total eclipse.
Why the Moon may look red
The red colour during lunar eclipses is caused by sunlight passing through Earth's atmosphere and being scattered; shorter blue wavelengths are removed, while longer red wavelengths are bent into the shadow and illuminate the Moon. This same scattering effect, which makes sunrises and sunsets appear red, can give eclipsed parts of the lunar surface a coppery or brick-red cast.
Skywatchers across the UK who have clear skies should be able to see the phenomenon with the unaided eye, though cloud cover will affect visibility. No special equipment is required to view a lunar eclipse, but binoculars or a small telescope can enhance surface detail.
Astronomers and amateur observers often use such events to study the Moon's surface and Earth's atmosphere, and partial eclipses offer an accessible opportunity for the public to observe celestial mechanics at work.