It's not really a spaceship

STRANGE FORMATION: Lenticular clouds, like this one seen in Island Bay, are stationary clouds that result from strong winds over rugged terrain and form at high altitudes.

It was in fact a lenticular, or lens-shaped, cloud. The natural phenomenon is commonly mistaken for a UFO.

Lenticular clouds – or altocumulus standing lenticularis – are stationary clouds that result from strong winds over rugged terrain and form at high altitudes.

MetService forecaster Rob Kerr, who lives in Island Bay and saw the cloud on Friday evening, said it was one of the best he had seen since a similar formation at Castlepoint three years ago.

"I didn't have a camera that day and it's the first time since that I've seen them lit up so well by the sun. I was jumping up and down like a kid in a toy shop."

Mr Kerr said lenticular clouds were common around the Wellington region "if you know what you're looking for". They can generally be seen over Mt Orongorongo in the Rimutaka Range.

"The odd thing about it is that the cloud stays still, it's like an eddy. But the air is actually flowing through the cloud at quite high speed and that's why they change shapes in quite odd ways."

Two weeks ago a large lenticular cloud – bathed in pink from a setting sun – appeared to hover above Mt Ruapehu.

- © Fairfax NZ News