Millions of people have the chance to see the most spectacular lunar eclipse in years tonight when the Moon will turn bright orange or red.

Lunar eclipses are when the Earth’s shadow from the Sun falls directly on the Moon and a change in the weather forecast means it is likely to be visible almost everywhere in the country. The colour of the Moon will change from silvery white to coppery red or orange as light is deflected by the Earth’s atmosphere and bounces back off the “blood moon”.

In ancient times blood moons were seen as omens of great change or disaster and were regarded with dread.

As the Earth passes between the Sun and the Moon light scattering through the atmosphere is reduced to predominantly red wavelengths, which reflect off the lunar surface.

Astronomers are confident that even with the naked eye stargazers will be treated to dramatic views of the eclipse, which will be at its height from 10.24pm to 11.58pm.

“With the Moon’s colour during totality ranging from dark coppery-brown to bright orange, it can be a most beautiful sight,” Ian Morison, of the University of Manchester’s Jodrell Bank Observatory, said. He said that the Moon would be invisible if it were not for the Earth’s atmosphere, which refracts and bends light from the Sun to illuminate the planet’s satellite.

“We can expect an impressive sight,” he said. “As blue light is scattered by the atmosphere more than red light, which is why our skies are blue, the light that remains is predominately red and orange — the colour of the Sun when close to the horizon. If there were astronauts on the surface of the Moon looking towards the Earth during a total lunar eclipse they would see a black disc surrounded by a bright red ring. It is the light from this ring that we see reflected by the Moon’s surface.”

It will be the best lunar eclipse over Britain since at least January 2001. The last one took place three years ago but few people were able to see it. Rain is expected to clear during today in time for a partial eclipse to begin at 8.16pm. The Moon will be completely in shadow by 10.44pm and the eclipse will be over at 2.25am.

Its brightness will depend on dust levels in the atmosphere.

The blood moon will be dimmer than full moons, let alone the Sun, so protective glasses are unnecessary. Astronomers said binoculars can be used to get a better view.

Total eclipses can occur only during full moons, which take place every 29.5 days. The eclipses are prevented from being a monthly event because the Moon’s orbit is inclined at 5 degrees to the Earth’s orbit around the Sun. The Earth’s shadow usually passes above or below the Moon.

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