Solar eclipse forecast to be the best for decades

Auckland Stardome astronomer Dr Grant Christie says the eclipse will take a "bite out of the sun". Photo / Brett Phibbs

Stargazers will be hoping for fine weather next Wednesday when a partial solar eclipse will blot out 91 per cent of the sun in some parts of the country.

Solar Saros 133, the series of eclipses which last gave New Zealand astronomers a treat almost two decades ago, is scheduled to begin at 9.18am over Auckland, reaching maximum coverage at 10.28am.

At its point of "maximum coverage", the sun would appear as a slim crescent - but would not have a significant effect on the amount of daylight, said Stardome's honorary astronomer, Grant Christie.

"If you've got safe solar viewers, you would see a bite out of the sun," Dr Christie said.

"The partial eclipse will gradually get bigger and bigger until it will look like a crescent shape, a bit like a moon, so the sun won't be a circular disc any more - it'll be a sliver of itself."

This would create a "dimming of light" if the day is clear.

"There wouldn't be too much difference to the amount of light you'd lose by having a cloud over the sun, so it's not going to have a strong effect."

But he warned that viewing the sun directly without a solar viewer could cause permanent blindness.

Over Auckland, about 87 per cent of the sun would be blocked out, he said, compared with up to 91 per cent in Northland's east coast but less than 60 in the far South Island.

The best vantage point was along the "path of totality" - a 180kmpath created by the shadow of the moon moving east from northern Australia, passing about midway between New Zealand and New Caledonia and finishing just before reaching the coast of Chile.

Coverage would reach 98 per cent at Norfolk Island, on the edge of the path, while cruise liners and aircraft were expected to position themselves along it.

Dr Christie expects thousands of Kiwis from outside the astronomy community will be watching out for the eclipse.

"You would have to go back 20 years to see anything like it ... and to see anything better you'd have to go back to 1965, when there was a total eclipse visible from New Zealand in the Far North.

"We hope the weather will be good, but frankly, it's been a pretty cloudy spring."