NZ to offer quick, rare view of Pluto

Pluto will pass in front of a star which will shine light back on far-flung dwarf planet. File image of Pluto/ Getty Images

Our country will next week offer international scientists a unique window to a quick and rare astronomical event that last occurred a decade ago.

The eclipse-like phenomenon, scheduled to begin about 5am on Tuesday, is also hoped to provide the world a quick glimpse of Pluto's atmosphere just a few weeks before NASA's spaceship, New Horizons, gets there.

In what is called a stellar occultation, Pluto will pass in front of a star which will shine light back on far-flung dwarf planet, giving scientists the best possible opportunity in nearly a decade to observe its atmosphere.

The occurrence is expected to last just 90 seconds.

"And it just so happens that the way things are positioned, one of the best places to observe this very short event is going to be over the south of New Zealand," NIWA atmospheric scientist Dr Richard Querel said.

At NIWA's atmospheric research station at Lauder in Central Otago, a part of the country renowned for its clear skies, Dr Querel and colleagues will watch on through powerful telescopes.

The star shining its light through Pluto's atmosphere will enable spectroscopic measurements to be made, allowing its atmosphere to be probed and studied.

The last time this happened, in 2006, significant discoveries about Pluto were able to be made from just a few seconds of exposure.

"It was around that time that a couple of new moons were discovered near Pluto that weren't known about before."

This time, researchers were particularly keen to see how the measurements they made from Earth compared with those from New Horizons as it soon flew by, collecting data and images never seen at such a short distance.

The information collected by the spacecraft was expected to provide a greater understanding of the origin and evolution of our solar system.

Several groups from the US and Europe were visiting the country, including some who travelled here for the last event.

Dr Querel said the scientists were still fine-tuning the precise timing and expected path of the shadow of the occultation, but there was a good chance of seeing something from Central Otago - provided the weather was clear.

"The forecast is for clouds at this stage, so we'll just have to wait and see."