Skywatchers in Hawke's Bay and parts of the South Island were treated to the bright green and red glow of the Aurora Australis last night.

Carter Observatory programmes officer John Field said the aurora, commonly known as the Southern Lights, could be seen in Hawke's Bay, where the weather was clear, and the few parts of the South Island without cloud cover.

The event, which started about 5pm, was brightest around midnight, he said.

It was triggered by a Coronal Mass Ejection (CME) - when the sun's magnetic fields collapse and pump solar particles into space - which occurred about three days ago.


"It lets out a huge wave of particles into the solar system and if it's pointing towards the earth, like this one was, it interacts with the atmosphere and makes the aurora active.''

One man who had written to the observatory said he saw the bright lights of the aurora from the roof of his Hawke's Bay house.

"In New Zealand we normally see a red glow along the horizon and then you may get green rays popping up and down. The further south you go you see more of the green, and you may see waves and patterns moving across the sky, so it can be quite stunning,'' Mr Field said.

CMEs can disrupt electronic systems in satellites and radio communication systems, but the latest event was not know to have caused any problems.