A rare event occurs on February 15th when a small Near Earth Object (NEO) asteroid passes within only 35,000 kilometres of the Earth, closer than even the ring of geostationary satellites orbiting our planet. Despite such close proximity, the asteroid, known as 2012 DA14, won't be visible to the naked eye but should be seen for a short time through binoculars or small telescopes.
2012 DA14 was discovered on February 23, 2012, by the OAM Observatory, La Sagra in Spain and is believed to be somewhere between 36 and 80 metres in size. If we assume that the asteroid is 50 metres across then it's about half the size of a football field. Give that its estimated mass is 130,000 metrics tons, this piece of rock is a fairly sizeable chunk of material.
However, there is no current or foreseeable danger of the object striking Earth. Its orbital characteristics are known to a high degree of accuracy and although at closest approach it will be only 0.000228 AU (34,100 kilometres or 21,200 miles) distant from Earth, there is absolutely no chance of collision.
Observing and star charts
Closest approach occurs at 19:24 UT on February 15th, when the asteroid should appear as a magnitude 7.2 star. Even the largest amateur telescopes wont show it as anything more than a point of light. Compared to the majority of Solar System objects, 2012 DA14 will zip across the sky. Its motion as well as brightness variations will be easily noticeable on the time scale of minutes as it skims past the Earth.
The best viewing location at closest approach will be Indonesia with Eastern Europe, Asia and Australia are also well situated to glimpse the asteroid. By the time observers on the Eastern Coast of the United States get the chance to see 2012 DA14, it will be a few hours past closest approach and down to a paltry 11th magnitude.
The charts below show the passage of 2012 DA14 as seen from London, England (51.5N, 0.1W) around the time of closest approach.
From the UK, the asteroid will not rise above the horizon until just before 20:00 UT, half an hour after closest approach. The magnitude of 2012 DA14 at this time is 7.6. Its rapid movement then takes it through Coma Berenices, Canes Venatici and into Ursa Major in the space of about 90 minutes. During this period it will be visible with binoculars, although by the time it reaches Ursa Major it will be down to 9th magnitude and much more difficult to detect.
Since the asteroid passes so close to Earth its path will vary, depending on location, relative to the background stars. For observers in Western Europe the path of the asteroid will be similar to that of the UK charts. For other locations the path will vary considerably. If you would like more accurate positional information then the NASA JPL ephemeris website can be used to generate the data for your specific location.
NASA JPL website ephemeris for 2012 DA14