Comet 46P/Wirtanen meteor shower: East Coast a prime spot for rare event

A “very rare” meteor shower is set to light up the sky above Hawke’s Bay and the rest of the country on Tuesday night - but cloud cover is threatening to spoil the show.

The one-off meteor shower has been caused by dust ejected from Comet 46P/Wirtanen.

That dust has formed into a “clump” which is headed toward Earth and will result in a meteor shower between 9pm and midnight tomorrow, pending clear skies.

While most regions across the country have cloudy weather forecast, stargazers will be hoping for some breaks in the clouds to enjoy the event.

Bay of Plenty has the clearest skies forecast and will provide the best vantage point.

Hawke’s Bay astronomy expert Gary Sparks said it was a “very rare” event and New Zealand was best placed to witness it.

Gary Sparks, who runs the Hawke's Bay Holt Planetarium, says it is a very rare event. Photo / Warren Buckland

“We are in the right place, at the right time.”

He said meteor showers were caused by comets - for the most part - which leave behind a trail of dust.

“Along comes the Earth orbiting the sun at 100,000km/h, and every year at the same time we pass through those trails of dust left behind by a comet during its orbit, and that is what causes meteor showers.”

This meteor shower is unique, in that it is a one-off event.

“What has happened in this case is this particular comet, Wirtanen, has left behind its trail of dust ... and during a couple of passes of Jupiter, that comet has sort of clumped the dust together.”

That clump of dust is on an unusual path and will collide with the Earth’s atmosphere on Tuesday night.

“This clump will exist for this one pass and we are going to plough through it and that is going to dissipate the whole thing.”

A former meteor shower visible from New Zealand. Photo / Stephen Voss

He said there was no danger to the planet. He said it would likely last a couple of hours but people should be patient watching.

Sparks said that, pending clear skies, anywhere with low light pollution would be best to watch including the coast, rural areas, or even atop Te Mata Peak.

“I certainly intend to go outside if it is clear for a couple of hours and park myself in a lawn chair out the back, and hope for the best.”

Unfortunately, MetService meteorologist Lewis Ferris said the weather was not looking great for viewing with “quite widespread cloud across the country”.

He said a south-westerly wind was going to push some rain and a “bank of cloud” up the country on Tuesday.

“That will reach Hawke’s Bay right around the time the show will be kicking off.

“As the day gets dimmer it looks like that cloud is going to increase.”

There is the possibility of breaks in the cloud but “I think any sort of breaks would be pretty brief”.

He said, looking at forecasts, Bay of Plenty would be the best region to view the meteor shower.

“That is the one spot that is looking to be the clearest.”

Keen stargazers can park near the gates of Te Mata Peak and walk to the top on the night.

Gary Hamilton-Irvine is a Hawke’s Bay-based reporter who covers a range of news topics including business, councils, breaking news and cyclone recovery. He formerly worked at News Corp Australia.