September 2022 – What’s Up!

Week of 26th September

  • Astronomical twilight ends at 20:49 BST at the beginning of the week and at 20:34 BST by the end of the week
  • Jupiter reaches opposition on Monday, the point in its orbit when it will be opposite the Sun from Earth. This is the best time to view the planet as it will appear largest and brightest in our sky as it is also at perigee, its point of closest approach to Earth. Jupiter will be 3.95 AU (591 million km) from Earth (its closest in 59 years!), with an apparent size of 49 arcseconds and a magnitude of -2.9. Look for the brightest object in our southern sky at an altitude of about 38° by midnight
  • The two lunar clair-obscur effects known as the lunar X and V will be visible in the early evening of Sunday, look along the terminator to find them. They are caused by sunlight catching certain parts of crater edges and higher regions
  • The Moon is Waxing Crescent all week
  • The Sun currently has six active regions: AR 3102, 3105, 3107, 3108, 3109 & 3110. The sunspot number is 128
  • The ISS makes the following visible evening passes this week:
    Monday 20:19, W to ESE, max 87° and 21:56, W, max 16°
    Tuesday 19:30, W to E, max 86° and 21:07, W to SW, max 43°
    Wednesday 20:18, W to SE, max 62° and 21:56, W to WSW, max 12°
    Thursday 19:30, W to ESE, max 77° and 21:07, W to SW, max 25°
    Friday 20:18, W to SSE, max 36°
    Saturday 19:29, W to SE, max 49° and 21:07, WSW to SW, max 13°
    Sunday 20:17, W to S, max 19°

Week of 19th September

  • Astronomical twilight ends at 21:07 BST at the beginning of the week and at 20:51 BST by the end of the week
  • The Autumn Equinox occurs at 01:58 BST on Friday. This is the point when the Sun crosses the celestial equator decreasing in declination. As the name suggests, we will enjoy an almost exactly equal day and night length of 12 hours and the event marks the start of autumn for the northern hemisphere. The Sun will rise due East and set due West, one of only two days in the year when this happens
  • Jupiter is brilliant in our evening and night sky at magnitude -2.9, outshone only by the Moon. This is an excellent time to observe the planet as it moves towards opposition. Use binoculars or a telescope to observe surface detail on the planet and enjoy the dance of its four Galilean moons as they orbit. Jupiter currently rises at around 19:15 BST, culminates at around 01:30 BST, reaching a maximum altitude of about 39°, and sets by about 07:30 BST
  • The Moon is New on Sunday
  • The Sun currently has three active regions: AR 3100, 3102 & 3103. The sunspot number is 76
  • The ISS makes the following visible evening passes this week:
    Monday 21:09, WSW to SE, max 76°
    Tuesday 20:21, WSW to E, max 60° and 21:57, W, max 26°
    Wednesday 21:09, W to ENE, max 86°
    Thursday 20:20, WSW to E, max 86° and 21:57, W, max 24°
    Friday 19:31, S to WSW to E, max 73° and 21:08, W to NW, max 85°
    Saturday 20:20, W to E, max 84° and 21:56, W, max 21°
    Sunday 19:31, W to E, max 87° and 21:08, W to WSW, max 67°

Week of 12th September

  • Astronomical twilight ends at 21:26 BST at the beginning of the week and at 21:09 BST by the end of the week
  • Neptune reaches opposition on Friday, when it lies opposite the Sun in the sky and will be at perigee, the closest point to Earth in its orbit. It is magnitude +7.8, so binoculars or a telescope will be required to observe the planet. Find it about 10° west of Jupiter in the south. It culminates at around 01:00 BST, so is well placed through the late evening
  • The planets are dominating our southern evening sky with Saturn (+0.4) furthest west, followed by Neptune (+7.8), Jupiter (-2.9), Uranus (+5.7) and finally Mars (-0.4) which rises at around 22:00 BST
  • The Moon is Last Quarter on Saturday
  • The Sun currently has eight active regions: AR 3092, 3094, 3096, 3097, 3098, 3099, 3100 & 3101. The sunspot number is 122
  • The ISS makes the following visible evening passes this week:
    Thursday 21:10, SSW to S, max 19°
    Friday 20:22, S to ESE, max 18° and 21:58, WSW, max 16°
    Saturday 21:09, SW to S, max 46°
    Sunday 20:21, SW to E, max 34° and 21:57, W, max 25°


Week of 5th September

  • Astronomical twilight ends at 21:46 BST at the beginning of the week and at 21:29 BST by the end of the week
  • Unfortunately, NASA’s attempted launch of Artemis 1 was not successful last week and further launch attempts are not likely until next month at the earliest
  • The waxing Gibbous Moon will make a close approach to Saturn (+0.4) on Thursday, when they will be separated by just 6°. Jupiter (-2.9) is rising ever higher in our evening sky, while Neptune (+7.8) lies to its west and Uranus (+5.7) to the east. Mars (-0.2) is now rising at around 22:30 BST as it moves towards opposition in December
  • The Moon is Full on Saturday – the Harvest Moon
  • The Sun currently has four active regions: AR 3089, 3092, 3093 & 3094. The sunspot number is 68
  • There are no visible evening ISS passes this week