Stargazers could spot a bright light in the sky days before Christmas as Saturn and Jupiter will come the closest they have done in hundreds of years, creating what researchers describe as a “spectacular event in the sky” on Monday 21 December – which also happens to be the winter solstice.
While conjunctions – where objects appear very close to each other in the sky – are not rare, this will be an “exceptionally close” one – the closest since 1623, Professor Michael Burton from Armagh Observatory and Planetarium said.
The two biggest planets in the Solar System will be just 0.1 degrees apart, one-fifth the diameter of the full moon, and appear together as the brightest object in the sky.
Prof Burton said: “When that happened it was in the daytime skies so people would not have seen it because it would have been too light.
“The last one which actually would have been well placed to be seen was 1226, so we’re going back 800 years to the last one which would have been up in the dark sky to be seen.”
The advice to keen stargazers is to look to the south west as soon as possible after sunset, with the best time between 4.30pm and 6pm, and while a telescope or binoculars will help, the phenomenon will be visible to the naked eye – weather permitting.
“We have to cross our fingers that there will be clear skies,” said Prof Burton.