This evening, most people in the UK have a chance of witnessing a total eclipse of the moon.
A lunar eclipse occurs when a full moon passes through the cone of shadow cast by the Earth into space.
Tonight's eclipse will begin before the moon has risen, but should then be visible for a couple of hours so long as the skies remain clear.
The eclipse first becomes total at 8.23pm, before reaching maximum totality at 9.13pm and ending at 10.03pm. The partial eclipse will end at 11.02pm.
People in the southern half of the UK will be able to see the moon totally eclipsed. But for people further north, most of the total phase will be over before the moon rises. Those in northern Scotland will miss totality entirely.
Dr John Mason, of the British Astronomical Association, explains: "The low brightness of the totally eclipsed moon, coupled with its low elevation above the horizon, will likely make the moon very difficult to see at, and for a time after, moonrise.
"The moon will be best located using binoculars or a wide-field telescope at this time. As the Moon rises higher in the sky it will become easier to see, but even from locations in south-eastern England there will be, at most, only about 50 minutes between moonrise and the end of the total phase."
There will be another lunar eclipse on 10 December 2011, but on this occasion the moon will have already started leaving the central part of the Earth's shadow before moonrise, so no part of totality will be visible from the UK.
To find out the approximate time of moonrise across the UK this evening, visit our eclipse map.
You can also send us your photos of the lunar eclipse. We'll publish a selection of them here on MSN.