Adrian Dening's Stars Over Somerset

Saturday, 28 December 2024 15:47

Monday 30th December 2024 to Sunday 5th January 2025

How about celebrating the beginning of the New Year with a simultaneous occultation and transit? Sounds a bit like some sinister black magic ceremony, but we're actually talking about a couple of Jupiter's Galilean moons!

From 9.45pm on Thursday 2nd, Ganymede is occulted by the planet as this largest of Jupiter's moons orbits behind the gas giant and so is blocked from our view. Ganymede reappears from behind Jupiter again at 11.50pm. At the same time, Io begins to transit in front of the planet and about half an hour later, it's shadow will be cast on the planet.

During the event, Jupiter will be very easy to spot, shining very brightly at a magnitude of around -2.7 and located towards the south, above the constellation of Orion. Mars will be to the left of them, shining at magnitude -1.2 which is also pretty bright!

Of course, although the planets themselves are easy "naked eye" objects, you will need a telescope to be able to see Jupiter's moons doing their thing! Our Solar System neighbours always look bright because they are relatively close to us and you can only see them because sunlight reflects off the planets' surfaces. Stars are fainter because they are much further away and radiating their own light.

The evening of Friday 3rd into the early morning hours of Saturday 4th sees the peak of the annual Quadrantids meteor shower. At midnight, the radiant point, where the shooting stars appear to originate from, will be located towards the north east.