Kiwi stargazers are in for an early Christmas treat as the solar system's two largest planets, Jupiter and Saturn (pictured), appear at their closest in more than 400 years. Photo / 123RF
Kiwi stargazers are in for an early Christmas treat as the solar system's two largest planets, Jupiter and Saturn (pictured), appear at their closest in more than 400 years. Photo / 123RF
Kiwi stargazers are in for an early Christmas treat as the two largest planets in the solar system, Jupiter and Saturn, appear at their closest since Galileo was alive 400 years ago.
Known as a Great Conjunction, the two planets will be visibly at their closest to each other on December 22, but also strikingly close between December 19 and 23.
Astronomers at Auckland's Stardome Observatory and Planetarium, are encouraging Kiwis young and old to look to the west from half an hour after sunset on these nights to see the rare astronomical event.
"The Great Conjunction refers to a time when the two largest planets in the solar system pass close to each other in the sky as viewed from Earth," Stardome astronomy educator John Rowe said.
"This is extremely exciting because it is the closest the two planets have appeared since 1623.
"And given the next time Jupiter and Saturn will be this close is 2080 - 60 years from now – this really is a rare once in a lifetime experience for most people."
This Great Conjunction is being referred to by many as the Star of Bethlehem because of the two points of light coming together at Christmas.
It represents the Three Wise Men following the star west to Bethlehem.
Rowe said the spectacle will be easily visible with the naked eye and will appear especially striking to spectators with clear views of the western horizon away from bright city lights.
"If you look low on the western horizon just to the right of where the sun sets, about half an hour or so after sunset, then you should get a great view – weather permitting of course.
"The planets will appear to sink quite quickly so are only going be visible for about an hour and a half each of the four evenings. Perfect timing for the kids to see before bedtime too."
The celestial phenomenon occurred because the planets were in line as viewed from Earth.
"While it looks like the planets are touching, they are in fact not even close to each other," Rowe said.
"Jupiter orbits the sun at a distance about five times greater than Earth, and Saturn about 10 times the Earth-Sun distance.
"Nonetheless, the view from here on Earth looks like a spectacular near-miss of the two largest planets in our solar system. It is going to be quite incredible to see."
Source / Stardome
Stardome astronomer Dr Grant Christie said although the planets would be at their closest points in our sky since the invention of the telescope, they weren't close in space.
"On December 21, Jupiter will be 763 million km from Earth while Saturn will be a further 856 million km beyond it."
Christie said the event coincided with some other big astronomical happenings. High up in the north of our night sky - appearing as a red and orange object - was Mars.
"It is currently quite close to Earth and won't be this close again until 2035," he said.
"As Jupiter and Saturn set, you will see Orion - part of which is commonly called The Pot - rising in the east together with the brightest star in the sky, Sirius."
The new moon would be close to Jupiter and Saturn tonight, and then on Wednesday and Thursday next week, would have moved nearer to Mars.
"The moon will also be close to Matariki - the Pleiades star cluster - on December 27," he said.
"With binoculars you can see many more stars belonging to this beautiful cluster. It lies about 440 light-years away in the constellation of Taurus."
The longest day of the year also happened to fall on December 21 - the same day Jupiter and Saturn would be closest to each other - but Christie added this was merely co-incidence.
