Stargazers heading to Aoraki-Mt Cook to witness a once-in-a-lifetime astronomy event taking place next month have been warned not to risk permanent eye damage by looking directly at the sun.
Between 10am and 5pm on June 6, the planet Venus will align directly between the sun and Earth and will be visible as it passes across the sun.
It is an event that will not happen again until 2117.
However, Big Sky Stargazing astronomy guide Leigh Findlay said, as the transit of Venus was occurring during the daytime, it was dangerous to view the rare phenomenon directly, and he encouraged people to take precautions or use the specialist set-up at the Sir Edmund Hillary Alpine Centre at Aoraki-Mt Cook.
"We warn people not to try to view the sun directly with the naked eye, or even through sunglasses, as they don't protect your eyes.
"At Big Sky Stargazing we have specialised equipment fitted with solar filters to view the transit of Venus ...
"We'll have guides there on the day, explaining the technology we use and what is actually happening during the event itself.
"New Zealanders alive today have never before had the chance to see a transit of Venus in our skies."
The planet last crossed the sun in 2004, but Sir Edmund Hillary Centre operations manager Rod Kentish said that event had not been visible from New Zealand.
Mr Kentish said Venus would be visible for six hours as a black disk against the sun and the centre's planetarium had equipment that could enlarge the view.
Transits of Venus happen in pairs, eight years apart, separated by a gap of 100 years.
The full cycle is repeated only once every 243 years.