Skywatchers across WA took up position last night to see the two biggest planets come closer together than they have since the days of Galileo.
Thousands flocked to the coast in Scarborough to catch a glimpse of the conjunction, known as the “Christmas Star”.
It’s known as this because some astronomers believe it’s the famous Star of Bethlehem from the Bible nativity story, according to the Perth Observatory.
Lines for five telescopes, set up by the Gravity Discovery Centre and Observatory, were hundreds deep as people waited patiently for their turn to see the galactic spectacle.
The Perth Observatory was also set up in North Coogee where big numbers gathered.
While not an actual star, the sight of Saturn and Jupiter appearing to “kiss” in the night sky is an event not seen for centuries.
The planetary action lit up skies across the world last night — and will do so for the next two weeks.
The event is an “especially vibrant planetary conjunction” easily visible in the early evening as the planets come together.
It is estimated that at the closest point of the conjunction, the planets will be separated by just one-tenth of a degree apart from our perspective or about one-fifth the width of a full moon.
Despite the illusion, the planets are actually more than 700 million kilometres apart.
According to NASA, the closest alignment will last for a few days and the planets will appear so close together that “a pinky fingers at arms-length will easily cover both planets in the sky”.
Toss in the winter solstice in the Northern Hemisphere, the longest night of the year — and the summer solstice in the Southern Hemisphere — and this spectacle is set to be one of the greatest of Great Conjunctions.
“What is most rare is a close conjunction that occurs in our night-time sky,” said Vanderbilt University’s David Weintraub, an astronomy professor.
“I think it’s fair to say that such an event typically may occur just once in any one person’s lifetime, and I think ‘once in my lifetime’ is a pretty good test of whether something merits being labelled as rare or special.”
Saturn and Jupiter have been drawing closer in the south-south-west sky for weeks. Jupiter — bigger and closer to Earth — is vastly brighter.
“I love watching them come closer and closer to each other and the fact that I can see it with my naked eyes from my back porch!” Virginia Tech astronomer Nahum Arav said in an email.
The last time Jupiter and Saturn were so close together was in 1623 and it was seen by Galileo.
But it was almost impossible to see because of its closeness to the Sun.
Considerably closer and in plain view was the conjunction of March 1226 — when Genghis Khan was conquering Asia.
Their next super-close pairing: March 15, 2080.