Southern Lights may return to Hawke's Bay

Hawke's Bay skywatchers were treated to the distant but unmistakable sight of the Aurora Australis flickering above the southern horizon on Monday night in a show which may return, if space conditions are right, during the next few days.

Faint red and green glows were reported by some skywatchers in Hastings, although the strongest displays were in the skies of the deep south.

"It is not the first time we've seen the Aurora recently," Napier astronomer Gary Sparks said.

"We had another sighting in the past five to six weeks."

The Aurora Australis, or Southern Lights, had begun to fire up recently in the wake of what astronomers describe as coronial mass ejections from the sun.

There had been a strong ejection about five days ago, with the charged solar particles being hurled off into space, where they reach earth about three days later.

Mr Sparks said the aurora was a celestial version of the fluorescent tube. The charged particles strike the strong magnetic fields around the poles of the earth and glow "like gas in a tube," he said.

The lights were not uncommon in New Zealand but were mainly seen in the South Island.

"The closer to the pole the better it is," Mr Sparks said, adding that to get a good view of the phenomenon the viewer needed a clear view to the southern horizon and no light pollution.

From Hawke's Bay the effect would be like seeing the shimmering lights of a distant city over the horizon.

The latest ejections were more evidence that the sun was building up to the peak of its cycle, which it would reach next year.

"Then we'll probably start seeing more [lights]," Mr Sparks said.

Auroras could be predicted, he said, although the Monday night aurora was stronger than expected.

On the website spaceweather.com it was noted "although the storm is subsiding, high-latitude sky watchers should remain alert for auroras".