September 2025 – What’s Up!

Week of 29th September

• Astronomical Twilight ends at 20:40 BST at the start of the week and at 20:26 BST by the end of the week.
• This week Saturn (+0.7) rises at around 18:30 BST; it is fascinating with its rings edge on to us and a multitude of moons stretching out either side. Jupiter (-2.1) rises at around 23:50 BST, and Venus (-3.9) rises at around 04:40 BST.
• Dwarf planets in our evening sky provide the observing challenge this week. Hunt down Ceres (+7.6), the closest to Earth at just under 2 AU away, which reaches opposition on Thursday. With that one in the bag, extend your reach to the outer solar system to find Pluto (+14.5) at about 35 AU away. The best way to spot these objects is though photography over multiple nights and look for the dot that moves!
• The Moon is First Quarter on Tuesday.
• The Sun currently has 10 active regions and the sunspot number is 172.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 22nd September

• Astronomical Twilight ends at 20:58 BST at the start of the week and at 20:43 BST by the end of the week.
• The September or Autumn Equinox is at 19:19 on Monday, this is when the Sun crosses the Celestial Equator heading south. It is one of only two days in the year when the Sun will rise due East and set due West. Day and night length will be equal at about 12 hours each. Happy Equinox!
• The planets are becoming ever more prominent in our night / evening sky with Saturn (+0.6) rising at 19:08 BST. You will find faint Neptune (+7.8) just over 2° to the east. Jupiter (-2.1) rises at around 00:25 BST this week, while Venus (-3.9) is moving back towards the Sun and rises at 04:25 BST.
• The Andromeda region of sky provides our challenge this week with globular cluster M15 (+6.2) first on the list in neighbouring Pegasus. Then move to Andromeda for M31 (+3.4), the Andromeda Galaxy, and on to the most challenging object, M76 (+10.1), the Little Dumbbell Nebula in next door Perseus.
• The Moon is Waxing Crescent all week.
• The Sun currently has 10 active regions and the sunspot number is 155.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 15th September

• Astronomical Twilight ends at 21:17 BST at the start of the week and at 21:01 BST by the end of the week.
• Saturn (+0.6) reaches opposition on Sunday, putting it in the best place for observation; it will appear largest and brightest from Earth. The ringed planet rises at 19:12 BST and transits at 01:05 BST – enjoy the view!
• Jupiter (-2.1) rises at around 00:35 BST this week and Venus (-3.9) rises at 04:10 BST.
• Look out for a lunar occultation of Venus on Friday, though extreme care must be taken as it will happen during sunlight hours, so ensure that you do not stray to the Sun if using an instrument. The occultation starts at 12:54 BST and Venus reappears at 14:11 BST.
• This week’s Deep Sky observing challenge is a tough one… inspired by this week’s Picture of The Week and the New Moon, try to catch a glimpse of the Veil Nebula in Cygnus. It is a very tough target to spot and aperture is definitely required, the more the better! The use of an OIII or UHC filter will help to bring out the tenuous veil of gas. Good luck!
• The Moon is New on Sunday.
• The Sun currently has 3 active regions and the sunspot number is 43.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 8th September

• Astronomical Twilight ends at 21:36 BST at the start of the week and at 21:19 BST by the end of the week.
• Watch the Waning Gibbous Moon rise with Saturn (+0.6) on Monday evening. Look to the eastern horizon at around 20:15 BST.
• Jupiter (-2.0) rises at around 01:10 BST this week and is in Gemini, forming a triangle with stars Castor (+1.6) and Pollux (+1.2). If you are up anyway, watch bright Venus (-3.9) rise at 03:44 BST.
• If you like double stars, this week’s observing challenge is for you as three fabulous doubles are in our evening sky: start with Albireo (+3.1) in Cygnus, Albireo means ‘beak’ in Arabic, then sticking with the nose theme, move to Gamma Delphini (+4.3) which forms the Dolphin’s rostrum or snout! Finish off in Andromeda with Almach (+2.2), the multicoloured double which sits at the foot of Andromeda, the beautiful daughter of Cepheus and Cassiopeia.
• The Moon is Last Quarter on Sunday.
• The Sun currently has 8 active regions and the sunspot number is 108.
• There are multiple visible evening ISS passes this week (click here for full ISS pass details).

Week of 1st September

• Astronomical Twilight ends at 21:57 BST at the start of the week and at 21:39 BST by the end of the week.
• There is a Total Lunar Eclipse on Sunday, the Full Harvest Moon will rise at 19:36 BST fully eclipsed. The Earth’s shadow will steadily move across the face of the Moon until the umbral eclipse ends at 20:57 BST and the penumbral eclipse ends at 21:55 BST. Find yourself a vantage point with a clear view of the Moon’s easterly rising point and you will be in for a spectacular celestial show!
• The planets are becoming increasingly prominent in our night sky as we continue our solar orbit with Saturn (+0.7) rising at 20:21 BST, Jupiter (-2.0) at 01:25 BST and Venus (-4.0) appearing at 03:30 BST.
• As the autumn creeps up on us, take a last view of the deep sky summer highlights in the west, starting with the ever spectacular Great Hercules Cluster (+5.8), then on to the multi-coloured double star Albireo (+5.1), and finish with a glimpse of the two wonderful summer planetary nebulae, the Ring Nebula, M57 (+8.8) and the Dumbbell Nebula, M27 (+7.1).
• The Moon is Full on Sunday – the Harvest Moon.
• The Sun currently has 10 active regions and the sunspot number is 183.
• There are no visible evening ISS passes this week (click here for full ISS pass details).