December 2025 – What’s Up!

Week of 29th December

  • Astronomical Twilight ends at 18:10 GMT at the start of the week and at 18:15 GMT by the end of the week.
  • The Earth reaches perihelion at 17:15 GMT on Saturday, its closest point to the Sun in its annual orbit. This makes summer in the southern hemisphere slightly hotter than in the northern hemisphere!
  • The Quadrantid meteor shower peaks on Saturday. It is one of the most productive showers of the year with a ZHR of 120, but that is in perfect conditions. Unfortunately, the Full Moon will drown out all but the brightest, but it is still worth watching the skies for the natural fireworks display! The shower’s progenitor is asteroid 2003 EH1.
  • Saturn (+1.2) is edging towards the end of its apparition as it now sets at around 23:00 GMT, catch it while you can. Meanwhile, Jupiter (-2.7), is moving towards centre stage, rising at around 17:00 GMT as it approaches opposition next week.
  • Given the Full Moon this week, the observing challenge is lunar; hunt for the following features: The Sea of Tranquillity, site of the Apollo 11 landing, the crater Tycho, with vast ejecta rays, and finally, the crater Copernicus in the Ocean of Storms.
  • The Moon is Full on Saturday – the Wolf Moon.
  • The Sun currently has 8 active regions and the sunspot number is 130.
  • There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 22nd December

  • Astronomical Twilight ends at 18:05 GMT at the start of the week and at 18:09 GMT by the end of the week.
  • The Ursid meteor shower peaks on Monday. It is not a prolific shower, with a ZHR of only 10 meteors. Its progenitor is comet 8P/Tuttle.
  • The four giant planets are in our night sky at the moment, from west to east: Saturn (+1.1) sets at around 23:30 GMT, Neptune (+7.9) is just a few degrees to the east, Uranus (+5.6) is in the south, transiting at around 21:44 GMT, and finally Jupiter (-2.6), which rises at around 17:30 GMT and transits at around 01:40 GMT.
  • Auriga is home to a plethora of open clusters, the best of which are M38 (+6.4), the Starfish Cluster, M36 (+6.0), the Pinwheel Cluster, and M37 (+5.6). Use your binoculars to enjoy this cluster rich patch of sky.
  • The Moon is First Quarter on Saturday.
  • The Sun currently has 6 active regions and the sunspot number is 74.
  • There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 15th December

  • Astronomical Twilight ends at 18:02 GMT at the start of the week and at 18:05 GMT by the end of the week.
  • The December Solstice is on Sunday at 15:04 GMT when the Sun reaches it lowest declination of -23.5°. It will then begin to climb higher in our northern hemisphere sky as we move through winter.
  • Saturn (+1.1) transits at around 18:20 GMT this week and sets at around 00:00 GMT. Jupiter (-2.6) rises at around 18:05 GMT and transits at around 02:00 GMT. There is an evening GRS transit on Thursday, starting at 18:20 GMT.
  • Taurus is the focus of the observing challenge this week. Start with the very large open cluster, the Hyades (+0.5), the V of the head of the Bull, with bright red giant star, Aldebaran (+1.0), is the eye of the Bull. Move up a few degrees to M45, the Pleiades (+1.5) or Seven Sisters – how many stars can you make out with the naked eye, and how many more can you see with binoculars?! Finish with a ‘faint fuzzy’, M1, the Crab Nebula (+8.4), a supernova remnant that will require a good telescope to tease out any structure.
  • The Moon is New on Saturday.
  • The Sun currently has 5 active regions and the sunspot number is 76.
  • There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 8th December

  • Astronomical Twilight ends at 18:02 GMT at the start of the week and at 18:02 GMT by the end of the week.
  • The Geminid meteor shower peaks on Sunday morning, so Saturday night should give the best observing opportunity. The ZHR is 120 meteors per hour, making it one of the finest showers of the year. Its progenitor is asteroid 3200 Phaethon. Let’s hope for clear skies!
  • Saturn (+1.1) transits at around 18:40 GMT this week and sets at around 00:25 GMT. Jupiter (-2.6) rises at around 18:35 GMT and transits at around 02:40 GMT. The GRS transit on Monday starts at 20:05 GMT, accompanied by a transit of Io, which ends at 21:18 GMT.
  • This week’s observing challenge is a daytime one; active regions 4294 and 4296 on the surface of the Sun are vast, and are currently perfectly placed to bombard Earth with charged particles if they erupt. Take great care when observing the Sun, only using suitable filters to ensure safety.
  • The Moon is Last Quarter on Thursday.
  • The Sun currently has 7 active regions and the sunspot number is 129.
  • There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 1st December

  • Astronomical Twilight ends at 18:03 GMT at the start of the week and at 18:02 GMT by the end of the week.
  • Mercury (-0.4) reaches Greatest Western Elongation on Sunday, making it observable in the pre-dawn twilight, about 9° above the south-eastern horizon. Take care of the Sun if using binoculars to try and find Mercury.
  • Saturn (+1.1) transits at around 19:05 GMT this week and sets at around 00:55 GMT. Jupiter (-2.5) rises at around 19:00 GMT and transits at around 03:10 GMT. Look out for a usefully timed GRS transit on Wednesday, starting at 20:58 GMT.
  • In search of bright objects this week, given the Full Moon, head to Auriga for three Messier open clusters. Start with M38 (+6.4) at 4,600 light years away, then on to M36 (+6.0) at 4,300 ly, and finally to M37 (+5.6) at 4,500 ly.
  • The Moon is Full on Thursday – the Super Cold Moon.
  • The Sun currently has 4 active regions and the sunspot number is 74.
  • There are multiple visible evening ISS passes this week (click here for full ISS pass details).
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