Cloudy weather in Auckland overnight prevented watchers at the Stardome Observatory from being able to see a 45-metre wide asteroid which came so close to Earth that it passed between the planet and some telecommunications satellites.

Asteroid  2012 DA14, estimated to weigh 130,000 tonnes, was the largest object for which predictions of a close to Earth flyby have been made.

Travelling at 28,100kmh, or 7.82km per second, the asteroid reached its closest point to the Earth around 8.25am today, coming within 27,700km.

Astronomer Dr Grant Christie at Auckland's Stardome Observatory and Planetarium had hoped to track the asteroid from early today, but spokesperson Jo Creagh said cloud cover meant it had not been possible to get pictures of the asteroid from Stardome. "We couldn't catch a glimpse of any stars overnight."

Nasa had been reassuring everyone that the asteroid posed no danger, and in the end the drama of such a close pass by something so big was overshadowed by the meteor that exploded over Russian skies yesterday evening.

About 1100 people were reportedly injured as a result of the meteor over the Ural Mountains, which exploded with the power of an atomic bomb and created sonic blasts that shattered windows.

Preliminary estimates by Nasa's Jet Propulsion Laboratory put the size of the meteor before it hit the atmosphere at 15 metres, with a mass of about 7000 tonnes. It was unconnected to asteroid 2012 DA14.

Had the asteroid hit Earth it would be expected to cause regional devastation, releasing about 2.5 megatons of energy in the atmosphere, Nasa said.

A slightly smaller asteroid about 30 to 40 metres across was believed to have flattened about 1200sqkm of forest in Tunguska, Siberia in 1908. 

- © Fairfax NZ News