Image copyright @iangriffin Image caption The cosmic light show was described as "spectacular" by Dr Ian Griffin

Passengers on board what is thought to be the first charter flight to view the Southern Lights have been left awestruck by the display.

The flight took off from Dunedin, New Zealand, on Thursday night, returning early on Friday to the same airport.

Otago Museum Director Dr Ian Griffin led the sold out expedition, which carried 134 people on its unique trip.

Speaking to the BBC, he said the "awesome" flight gave everyone "a spectacular display".

"Nobody has ever really done that before. This was a world first. People have done it in the northern hemisphere," he said, stressing that it was not as straightforward to plan as a normal flight.

"The aurora doesn't just appear in specific locations, it can move around a bit, and we were trying to chase it across the Southern Ocean, which was quite fun."

Image copyright @iangriffin

Passengers on the Air New Zealand flight, which was deliberately not fully booked so everyone could see out of the windows, were treated to spectacular displays visible to the naked eye.

The Boeing 767 flew through the aurora zone several times, going as far as 66 degrees south, or "two-thirds of the way to the south pole", in Dr Griffin's words.

Image copyright @iangriffin Image caption In this photo, shot 60 degrees south of equator, the moon is a blazing point of light

For some passengers the trip was especially memorable.

"I can't ever imagine another experience quite like it in my lifetime... sipping champagne, eating a special aurora cupcake at 0001hrs 66S... as I welcomed the dawn of a new decade in my life, has to be up there with the very best life can offer," commented Frith Walker on Facebook.

Fellow passenger Taichi Nakamura was similarly grateful: "It was so amazing to see the huge auroras very close during the successful mission."

Image copyright @iangriffin

Despite the cost of tickets - NZ$4,000 ($2,800; £2,244) in economy, NZ$8,000 in business class - organisers expect to repeat the flight later in the year or in 2018.

The Aurora Australis is caused by the interaction of solar wind - a stream of charged particles escaping the Sun - and Earth's magnetic field and atmosphere.