December 2023 – What’s Up!

Week of 25th December

  • Astronomical twilight ends at 18:07 UT at the start of the week and at 18:11 UT by the end of the week.
  • Saturn (+0.9) sets at around 21:10 UT through this week while Jupiter (-2.6) culminates at around 20:00 UT. There is a double shadow transit (Europa and Ganymede) across Jupiter on Saturday between at 22:16 and 23:56.
  • Comet 62P/Tsuchinshan reaches perihelion on Monday and peak brightness on Thursday, though it will still only be magnitude +9.2, so a telescope will be needed. Find the comet in Leo, passing by the Leo Triplet on Thursday.
  • The Moon is Full on Wednesday – the Cold Moon.
  • The Sun currently has 10 active regions and the sunspot number is 123.
  • There are no visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).

 

Week of 18th December

  • Astronomical twilight ends at 18:03 UT at the start of the week and at 18:06 UT by the end of the week.
  • The Winter Solstice is on Friday when the Sun will reach its lowest declination of -23.5° at 03:24 UT. It will be the shortest day of the year and marks the start of winter here in the Northern Hemisphere.
  • Saturn (+0.9) culminates at around 16:30 UT through this week, and Jupiter (-2.7) culminates at around 20:25 UT. There is a transit of Io starting at 21:51 on Friday.
  • The Ursid meteor shower peaks on Friday, though don’t expect to see many Ursids, it is a minor shower, with only around 5 to 10 meteors per hour, nothing in comparison to the recent Geminids. The radiant is in Ursa Minor and the progenitor is comet 8P/Tuttle.
  • The Moon is First Quarter on Tuesday.
  • The Sun currently has 11 active regions and the sunspot number is 163.
  • There are no visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).

Week of 11th December

  • Astronomical twilight ends at 18:02 UT at the start of the week and at 18:03 UT by the end of the week.
  • Saturn (+0.9) culminates at around 16:55 UT through this week, and Jupiter (-2.8) culminates at around 20:5 UT. Look out for transits of the GRS at 19:00 UT and Io at 20:00 UT on Friday evening.
  • The Geminid meteor shower peaks on Thursday evening. It is one of the finest showers of the year, producing around 80 to 100 meteors per hour. The Moon phase is favourable this year, so, if clear, it should be a great show! The progenitor of the shower is asteroid 3200 Phaethon.
  • This week’s Deep Sky Object is the Great Orion Nebula, M42, a star forming region about 1,400 light years from Earth. Visible as a fuzzy area below Orion’s Belt, binoculars or a telescope will reveal the extent of the object’s nebulous nature. Try to spot the four brightest stars of The Trapezium, the open cluster at the centre of the nebula.
  • The Moon is New on Tuesday.
  • The Sun currently has 8 active regions and the sunspot number is 125.
  • There are no visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).

Week of 4th December

  • Astronomical twilight ends at 18:02 UT at the start of the week and at 18:01 UT by the end of the week.
  • Mercury reaches Greatest Eastern Elongation on Monday, making it best placed for observation in the evening sky. Look close to the southwestern horizon around sunset (16:00 UT) to spot the planet, but take care of the Sun if using binoculars.
  • Saturn (+0.9) culminates at around 17:20 UT through this week, while Jupiter (-2.8) culminates at around 21:20 UT. There is a transit of Io on Friday, starting at 18:14 UT, which coincides with the GRS being visible, use a telescope to enjoy the view.
  • This month’s Deep Sky Challenge is in Taurus, spot Messier 1 – The Crab Nebula between the horns of the bull. This supernova remnant is faint at mag +8.4, so a telescope will be needed to spot the ‘fuzzy blob’. Chinese astronomers recorded the associated supernova in 1054. The remnant has now expanded to cover 6 arcminutes of sky at about 6000 light years from Earth.
  • The Moon is Last Quarter on Tuesday.
  • The Sun currently has 10 active regions and the sunspot number is 92.
  • There are multiple visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).