October 2021 – What’s Up!

Week of 25th October

  • Astronomical twilight ends at 19:45 BST at the start of the week and at 18:34 GMT by the end of the week
  • Daylight Saving Time ends on Sunday and the clocks move from BST back one hour to rejoin GMT
  • Marlborough Dark Skies Festival is on all week, with the Museum of the Moon in the College Chapel and multiple events lined up for the weekend – check the festival website for full details
  • Mercury reaches Greatest Elongation West on Monday, making it visible in the eastern morning sky at an altitude of about 14°
  • Venus reaches Greatest Elongation East on Friday and is visible at an altitude of about 9° in the southwestern sky just after sunset
  • Saturn (+0.6) and Jupiter (-2.5) are visible in our western evening sky. Saturn now sets before midnight, so this apparition is approaching completion
  • The Moon is Last Quarter on Thursday
  • The Sun currently has 2 active regions: AR2886 and AR2887. The sunspot number is 32
  • There are no visible evening ISS passes this week

Week of 18th October

  • Astronomical twilight ends at 19:58 BST at the start of the week and at 19:47 BST by the end of the week
  • The Orionid meteor shower peaks on Thursday. It is a relatively small shower, with a ZHR of only around 15, caused by debris deposited by comet 1P/Halley. Its radiant appears in the constellation of Orion. Unfortunately, the Full Moon this year will drown out all but the brightest meteors
  • Saturn (+0.6) and Jupiter (-2.6) are moving ever further West in our evening sky, so enjoy the beautiful gas giants now, while they are still visible
  • The Moon is Full on Wednesday – the Hunter’s Moon
  • The Sun currently has 1 active region: AR2882. The sunspot number is 11
  • There are no visible evening ISS passes this week

Week of 11th October

  • Astronomical twilight ends at 20:13 BST at the start of the week and at 20:00 BST by the end of the week
  • Venus (mag -4.3) is currently visible low to the horizon in the southwestern sky around sunset
  • Saturn (+0.5) and Jupiter (-2.6) continue to dominate our southern evening sky. They will be joined by the waxing crescent Moon on Thursday and Friday
  • The Moon is First Quarter on Wednesday
  • The Sun currently has 1 active region: AR2882. The sunspot number is 14
  • There are no visible evening ISS passes this week

Week of 4th October

  • Astronomical twilight ends at 20:29 BST at the start of the week and at 20:15 BST by the end of the week
  • Saturn (+0.5) and Jupiter (-2.7) provide the highlight of our evening sky. On Monday, watch a double moon shadow transit across Jupiter as the shadows of Callisto and Ganymede move across the planet’s disk from 19:51 to 23:26 BST
  • The peak of the Draconids meteor shower is on Thursday. It is a minor shower caused by debris from comet 21P/Giacobini-Zinner, with a ZHR of only 10 meteors, though it has produced much higher outbursts in recent years
  • The Moon is New on Wednesday
  • The Sun currently has 2 active regions: AR2877 and AR2880. The sunspot number is 25
  • The ISS makes multiple visible evening passes this week as follows:
    Monday: 20:10, W to S, max 16°
    Tuesday: 19:23, W to SSE, max 23°
    Thursday: 19:26, WSW to SSW, max 11°
in What's Up