"It's only every few years that a full moon happens to coincide with the part of the Moon's orbit when its closest to the Earth" - Marek Kukula, an astronomer at the UK's Royal Observatory.
Dr Tim O'Brien from the Jodrell Bank Observatory in Manchester gives you his tips for how to make the most of the night sky this evening. The moon will be closest to the earth and highest in the sky at 9.48pm tonight. The meteor shower - where what look like shooting stars fly across the sky - will be best after midnight but you will see some before then.
If the full moon tonight looks unusually large, it is not your imagination it is the biggest and brightest full moon to be seen for 15 years.
Each month the Moon makes a full orbit around the Earth in a slightly oval-shaped path, and tonight it will swing by the Earth at its closest distance, or perigee. It will pass by 356,613km away, which is about 28,000km closer than average. The unusual feature of tonight is that the perigee also coincides with a full moon, which will make it appear 14 per cent bigger and some 30 per cent brighter than most full moons this year so long as the clouds hold off from blocking the view. The next closest encounter with a full moon this large will not be until November 14, 2016.
A 'leap second' will be added onto the final minute of 2008 because the planet is gradually slowing down as it spins on its axis. The tweak will help correct the time-lag which shows up on ultra-accurate atomic clocks.
Those thinking about bundling up to watch the Geminids meteor shower this Saturday night may want to wait until the Jan. 4 Quadrantids instead. A full moon likely will mask all but the very brightest meteors during the shower. In addition, the shower peaks at 4 p.m. Utah time, too early for the best viewing.
Biggest Full Moon of the Year Some full Moons are genuinely larger than others and this Friday's is a whopper. Why? The Moon's orbit is an ellipse with one side 50,000 km closer to Earth than the other: diagram. In the language of astronomy, the two extremes are called "apogee" (far away) and "perigee" (nearby). On Dec. 12th, the Moon becomes full a scant 4 hours after reaching perigee, making it 14% bigger and 30% brighter than lesser full Moons we've seen earlier in 2008.
Occultation of the Pleiades On the 10-11th December the nearly full moon (97%) will occult the Pleiades. The event will be visible from North America and Eastern Asia.
Disappearance Times:
Anchorage 6:24 UT San Francisco 6:53 UT New York 7:45 UT
If youve got some late-night time to spare and its not too cold outside, then you might want to look toward the sky and enjoy the yearly December meteor showers. Beginning tonight and running through Dec. 18, the Geminids are expected to streak all over the sky, with experts saying up to 120 to 160 shooting stars per hour will be visible from the east. The best night to look for the Geminids will be Dec. 14.
The Geminid Meteor Shower radiates from the constellation Gemini in the northeast, and will produce fast and bright meteors. Unfortunately a bright moon may hamper viewing.