A total lunar eclipse is due to take place on Saturday afternoon.
The best views of the eclipse, which will result from the Sun, the Moon and the Earth falling almost exactly in line, are expected to be available along the Pacific Rim, including throughout East Asia, Australia and Russia.
Stargazers in the UK will be able to see a partial eclipse, while the best view, weather permitting, will be available in the Shetland Islands.
Dr Robert Massey, of the Royal Astronomical Society, described viewing an eclipse as a "spectacular" experience.
"Those with a good view will see the Moon with a reddish tinge, which can vary in intensity as the Sun's light is refracted through the Earth's atmosphere - it can be quite stunning," he said.
The eclipse will begin at 11:32 GMT, when the Moon enters the lightest part of the Earth's shadow. The total eclipse will then start at 14:06 GMT and end at 14:58, with the Moon emerging completely at 16:18.
"The UK generally will only get a view of the end of the eclipse, with the Moon close to the horizon. The further northeast you get, the more you will see," Dr Massey said.
He encouraged everyone who can to try to catch a glimpse of the eclipse, since "it's not something you see every day".