Taking a single shot over a long period is a "really brave" choice, said Winterstellar Charitable Trust chairman Andy Davey.
"It only takes a car going by or a gust of wind to change everything."
He is referring to an image titled Blackhead Star Trail which was the Natural Category runner-up for photographer Yang Zheng, who also won the Jury Prize with his image of the Mt Cargill communications tower in Dunedin.
Mr Davey, who has been photographing night skies for four or five years, said the best shots require "good conditions, experience, equipment — and luck, in a lot of cases".
Often the best shots were not what you planned, he said.
"You point your camera one way, then you turn around and see something completely different."
Board secretary Vicky Bowman said she had started photographing auroras six or seven years ago and had a "really good mentor" who taught her how to get the required effects.
"The first time I shot a decent aurora, I almost fell off my chair," she said.
Mr Zheng only came to New Zealand two years ago.
"I live in Dunedin and take care of my two young sons, which gives me a lot of free time to shoot the beautiful stars in New Zealand. We loved the scenery in New Zealand, so we tried to capture it with photos," he said.
The Winterstellar Exhibition is open to the public at Central Stories from today until August 28, and at Lakes District Museum and Gallery in Arrowtown from July 23-August 31. Photographs will be rotated between the galleries.
