What’s Up

Week of 28th March

• Astronomical twilight ends at 21:30 BST at the start of the week and at 21:43 BST by the end of the week
• On Monday morning, just before sunrise (at 06:51 BST), planets Venus (mag -4.3), Saturn (+0.9) and Mars (+1.1) appear close together about 9° above the southeastern horizon and are joined by the waning crescent Moon (-5.4)
• The Moon is New on Friday
• The Sun currently has three active regions: AR 2974, 2975 & 2976. The sunspot number is 48
• There are multiple visible evening ISS passes this week as follows:
  Monday 21:37, W to SSW, max 45°
  Tuesday 20:49, W to SE, max 60° and 22:26, W to WSW, max 14°
  Wednesday 21:38, W to SSW, max 25°
  Thursday 20:49, W to SSE, max 34°
  Friday 21:39, WSW to SSW, max 12°
  Saturday 20:51, W to S, max 12°

Week of 21st March

• Astronomical twilight ends at 20:16 UT at the start of the week and at 21:28 BST by the end of the week
• The clocks go forward one hour on Sunday; at 01:00 UT it will become 02:00 BST, the start of British Summer Time and daylight saving
• With the waning Moon and before the clocks change, this week is a good opportunity to enjoy the delights of Orion and the Winter Wreath as that portion of sky slips ever westwards. Meanwhile, the eastern sky, with Arcturus, the Spring Marker star rising, is home to a myriad of galaxies
• The Moon is Last Quarter on Friday
• The Sun currently has two active regions: AR 2965 & 2972. The sunspot number is 29
• There are multiple visible evening ISS passes this week as follows:
  Monday 19:45, WSW to E, max 59° and 21:28, W, max 19°
  Tuesday 18:58, SW to E, max 44° and 20:34, W, max 77°
  Wednesday 19:46, WSW to E, max 86° and 21:23, W, max 22°
  Thursday 18:58, WSW to E, max 73° and 20:35, W to NW, max 85°
  Friday 19:47, W to E, max 84° and 21:24, W, max 22°
  Saturday 18:59, W to E, max 87° and 20:36, W to SSW, max 74°
  Sunday 20:48, W to ESE, max 86° and 22:25, W, max 20°

Week of 14th March

• Astronomical twilight ends at 20:02 UT at the start of the week and at 20:14 UT by the end of the week
• The Spring Equinox is on Sunday, when we will enjoy almost exactly 12 hours of night and 12 hours of day. The Sun will rise exactly in the East and set exactly in the West. The actual moment that the Sun crosses the celestial equator moving from south to north is at 15:27 UT. This marks the first day of spring here in the northern hemisphere
• Venus reaches Greatest Western Elongation on Sunday, when it will be at its largest separation from the Sun, 46° apart. It will be shining brightly at magnitude -4.4 about 13° above the southeastern horizon at sunrise
• The Moon is Full on Friday – the Worm Moon
• The Sun currently has five active regions: AR 2960, 2964, 2965, 2966 & 2967. The sunspot number is 93
• There are multiple visible evening ISS passes this week as follows:
  Thursday 19:46, S to SSE, max 15°
  Friday 18:58, SSE to ESE, max 12° and 20:32, SW to SW, max 23°
  Saturday 19:45, SW to SE, max 33° and 21:21, WSW to WSW, max 13°
  Sunday 18:57, SSW to E, max 24° and 20:33, WSW to SW, max 52°

Week of 7th March

• Astronomical twilight ends at 19:49 UT at the start of the week and at 20:00 UT by the end of the week
• Leo, Virgo and Coma Berenices are well placed this week, ideal for exploration of their plethora of galaxies
• Early risers can spot Mars (mag +1.2) and Venus (-4.5) in the southeastern morning sky just before sunrise
• The Moon is First Quarter on Thursday
• The Sun currently has six active regions: AR 2955, 2957, 2958, 2960, 2961 & 2962. The sunspot number is 95
• There are no visible evening ISS passes this week

Week of 28th February

• Astronomical twilight ends at 19:36 UT at the start of the week and at 19:47 UT by the end of the week
• New Moon this week provides the perfect dark skies to attempt the Messier Marathon – try and spot all 110 Messier objects in one night!
• Mars (mag +1.3) and Venus (-4.6) grace our southeastern morning sky this week just before sunrise
• The Moon is New on Wednesday
• The Sun currently has two active regions: AR 2954 & 2955. The sunspot number is 22
• There are no visible evening ISS passes this week

Week of 21st February

• Astronomical twilight ends at 19:24 UT at the start of the week and at 19:35 UT by the end of the week
• On Sunday there is a morning gathering of solar system objects. Find the waning Crescent Moon close to Mars (mag +1.3), Venus (-4.6), Mercury (-0.1) and Saturn (+0.8). Look just above the southeastern horizon at around 07:00 UT, but avoid the rising Sun, especially if looking with binoculars
• With a waning Moon, this week’s dark evening skies will be ideal for deep sky hunting with binoculars; find two beautiful open clusters in Cancer: M44 – The Beehive Cluster (+3.1) and M67 (+6.9)
• The Moon is Last Quarter on Wednesday
• The Sun currently has four active regions: AR 2946, 2948, 2952 & 2953. The sunspot number is 51
• There are no visible evening ISS passes this week

Week of 14th February

• Astronomical twilight ends at 19:13 UT at the start of the week and at 19:23 UT by the end of the week
• On Wednesday, Mercury (mag 0.0) reaches greatest western elongation, making it appear at its highest altitude in our morning sky at about 8° above the southeastern horizon
• Look about 10° further to the west to spot Venus (-4.6) and Mars (+1.3) gracing our morning sky
• The Moon is Full on Wednesday – the Snow Moon
• The Sun currently has four active regions: AR 2939, 2940, 2941 & 2944. The sunspot number is 78
• There are no visible evening ISS passes this week

Week of 7th February

• Astronomical twilight ends at 19:01 UT at the start of the week and at 19:11 UT by the end of the week
• On Monday, the 6 day old, waxing crescent Moon (mag -7.1) will appear just 1° away from Uranus (+5.8) in the sky
• On Sunday, Venus (-4.6) will be at its highest altitude in the morning sky. Look about 16° above the southeastern horizon at around 07:30 UT, just before sunrise to spot the bright planet
• The Moon is First Quarter on Tuesday
• The Sun currently has four active regions: AR 2938, 2939, 2940 & 2941. The sunspot number is 91
• There are no visible evening ISS passes this week

Week of 31st January

• Astronomical twilight ends at 18:50 UT at the start of the week and at 19:00 UT by the end of the week
• Two comets are potential observing targets in the dark skies of the New Moon this week. Comet 19P/Borrelly is at mag +7.9 in Pisces and comet C/2019 L3 (ATLAS) is a trickier target at mag +12 in Gemini. A telescope and good seeing will be essential for success
• Mercury (+0.4) is at its highest altitude in the morning sky on Sunday. Look at an altitude of about 7° in the southeast at around 07:30 UT before sunrise. Venus will be shining brightly at mag -4.6 about 10° further west
• The Moon is New on Tuesday
• The Sun currently has four active regions: AR 2934, 2935, 2936 & 2937. The sunspot number is 74
• There are multiple evening ISS passes this week as follows:
  Monday: 18:04, W to ESE, max 72° and 19:41, W to WSW, max 21°
  Tuesday: 18:53, W to SSE, max 32°
  Wednesday: 18:04, W to SE, max 43° and 19:43, WSW to SSW, max 11°
  Thursday: 18:54, W to S, max 17°
  Friday: 18:05, W to SSE, max 23°
  Sunday: 18:07, WSW to SSW, max 12°

Week of 24th January

• Astronomical twilight ends at 18:40 UT at the start of the week and at 18:49 UT by the end of the week
• With a waning Moon giving dark evening skies, this is a good week to explore the Deep Sky delights of Orion. From star birth in The Orion Nebula (M42), to the ageing red supergiant, Betelgeuse and the hot supergiant double star, Alnitak, in Orion’s Belt
• The Moon is Last Quarter on Tuesday
• The Sun currently has two active regions: AR 2933 & 2934. The sunspot number is 22
• There are multiple evening ISS passes this week as follows:
  Monday: 17:14, SW to E, max 35° and 18:50, W to SW, max 86°
  Tuesday: 18:02, WSW to E, max 76° and 19:39, W, max 23°
  Wednesday: 18:51, W to NNE, max 84°
  Thursday: 18:03, W to E, max 86° and 19:39, W, max 24°
  Friday: 18:51, W to SE, max 84°
  Saturday: 18:03, W to E, max 87° and 19:40, W, max 25°
  Sunday: 18:52, W to SSE, max 57°

Week of 17th January

• Astronomical twilight ends at 18:30 UT at the start of the week and at 18:39 UT by the end of the week
• Try to spot Comet 19P/Borrelly in our southwestern evening sky. The comet is approaching perihelion on 1st February and lies just 1.2 AU away from Earth now. It is about magnitude +8, so binoculars or a telescope will be required. Look at an altitude of around 28° in Cetus, on the border with Pisces. A planetarium app will be useful to help locate the comet
• The Moon is Full on Monday – the Wolf Moon
• The Sun currently has eight active regions: AR 2924, 2925, 2926, 2927, 2929, 2930, 2931 & 2932. The sunspot number is 120
• There are multiple evening ISS passes this week as follows:
  Tuesday: 18:50, S, max 14°
  Wednesday: 18:03, SSE to SE, max 13° and 19:38, SW, max 13°
  Thursday: 18:51, SW to S, max 32°
  Friday: 18:04, SSW to ESE, max 27° and 19:40, WSW, max 18°
  Saturday: 17:18, S to E, max 19° and 18:53, WSW to SSW, max 58°
  Sunday: 18:07, SW to E, max 50° and 19:43, W, max 19°

Week of 10th January

• Astronomical twilight ends at 18:22 UT at the start of the week and at 18:29 UT by the end of the week
• Mercury (mag +0.1) reaches its highest altitude in the evening sky on Wednesday. Look at about 12° above the southwestern horizon just after sunset (16:23 UT) to observe the innermost inferior planet. It sits just 3° away from Saturn (0.7)
• The Moon is Waxing Gibbous all week
• The Sun currently has two active regions: AR 2924 & 2925. The sunspot number is 31
• There are no visible evening ISS passes this week

Week of 3rd January

• Astronomical twilight ends at 18:14 UT at the start of the week and at 18:20 UT by the end of the week
• The Quadrantid meteor shower peaks on Monday. This is one of the more spectacular annual showers, with a ZHR of around 120. The shower is active from 12 December to 12 January, as the Earth moves through debris deposited by asteroid 2003 EH1. The radiant of the shower is in the defunct constellation of Quadrans Muralis, an area of the sky now in the constellation of Bootes. The New Moon will make observing conditions ideal, if there is no cloud
• The Earth reaches perihelion on Tuesday morning, the point in its orbit that is closest to the Sun, when it will be just 0.9833 AU away. This will make the Sun appear at its largest in the sky, but given that the annual variance is only about 3%, it will be unnoticeable
• The Moon is First Quarter on Sunday
• The Sun currently has four active regions: AR 2916, 2918, 2922 & 2923. The sunspot number is 52
• There are no visible evening ISS passes this week

Week of 27th December

• Astronomical twilight ends at 18:08 UT at the start of the week and at 18:13 UT by the end of the week
• If the sky ever clears, it will be possible to view six planets in a line this week, starting with Mercury (mag -0.7) closest to the southwest horizon just after sunset at around 16:05 UT, next is Venus (-4.4), then Saturn (+0.7) and Jupiter (-2.2). As the sky reaches astronomical darkness, look for Neptune (+7.9) in the south and Uranus (+5.7) in the southeast
• For the early risers, add Mars (+1.5) to the planetary tally as it rises in the southeast at around 06:15 UT this week. It will be joined by the waning crescent Moon on Friday morning. To complete the solar system line up, spot the eighth and final planet by looking towards your feet!
• The Moon is Last Quarter on Monday and New on Sunday
• The Sun currently has seven active regions: AR 2908, 2912, 2915, 2916, 2917, 2918 & 2919. The sunspot number is 128
• There are no visible evening ISS passes this week

Week of 20th December

• Astronomical twilight ends at 18:04 UT at the start of the week and at 18:08 UT by the end of the week
• The Winter Solstice is on Tuesday, which will be the shortest day in the Northern Hemisphere and the first day of astronomical winter. The Sun will reach its lowest point in the sky at -23.5° declination. From this point on, it will be rising higher and higher and the days will lengthen as we head back towards summer – Happy Solstice!
• The Ursid meteor shower peaks through Tuesday night with its radiant in the constellation of Ursa Minor. It is not a particularly spectacular shower, with a ZHR of only around 10 meteors per hour, and the bright Moon is a hinderance, but you might spot a meteor caused by the debris deposited by comet 8P/Tuttle
• The planets Venus (mag -4.6), Saturn (+0.7) and Jupiter (-2.2) continue to adorn our evening sky in a line over the southwestern horizon around sunset
• The Moon is Waning Gibbous all week
• The Sun currently has six active regions: AR 2906, 2907, 2908, 2909, 2910 & 2911. The sunspot number is 117
• There are no visible evening ISS passes this week

Week of 13th December

• Astronomical twilight ends at 18:02 UT at the start of the week and at 18:04 UT by the end of the week
• The week starts with the ‘King’ of meteor showers, the Geminids. Its ZHR is upwards of 120, so can be spectacular. Unfortunately, the waxing gibbous Moon will drown out the fainter meteors this year. The shower is active from 7th to 17th December, with its peak on Monday night. Unusually for meteor showers, it is caused by debris deposited by an asteroid, Phaethon
• Venus (mag -4.7) reaches its highest altitude in our evening sky on Monday at about 13° above the southwestern horizon at 16:30 UT. Saturn (+0.7) and Jupiter (-2.2) complete a beautiful planetary twilight line up
• Comet C/2021 A1 Leonard, currently grazing our southwestern horizon at sunset, is about to sink lower, becoming visible only from more southerly latitudes by the middle of the week. It reaches perigee on Monday and perihelion on 2022-01-03
• The Moon is Full on Sunday
• Following an increasingly active year, the Sun currently has no active regions, though a new sunspot is emerging around the oncoming limb
• There are no visible evening ISS passes this week

Week of 6th December

• Astronomical twilight ends at 18:02 UT at the start of the week and at 18:02 UT by the end of the week
• The waxing Crescent Moon parades past the naked eye planets this week, near to Venus (mag -4.7) on Monday, Saturn (+0.7) on Wednesday and Jupiter (-2.3) on Thursday
• Comet C/2021 A1 Leonard, currently visible in our pre-dawn sky in binoculars at around mag +7, will become visible in our evening sky this week. Look 40 to 50 degrees further west of Venus at a similar altitude at around 16:30 UT to try and spot the comet. Predictions suggest that it could even become naked eye visible by the end of the week
• The Moon is First Quarter on Saturday
• The Sun currently has 3 active regions: AR2901, AR2902 and AR2904. The sunspot number is 35
• There are visible evening ISS passes this week as follows:
  Monday: 16:59, W to SE, max 46° and 18:37, WSW to SSW, max 12°
  Tuesday: 17:49, W to S, max 18°
  Wednesday: 17:01, W to SSE, max 25°
  Friday: 17:04, WSW to SSW max 12°

Week of 29th November

• Astronomical twilight ends at 18:04 GMT at the start of the week and at 18:02 GMT by the end of the week
• Venus (mag -4.7), in waning crescent phase, is low in our southwestern evening sky around sunset, setting itself at around 18:40
• On Saturday, there is a total solar eclipse, but unfortunately for us, it is only visible from Antarctica. A partial solar eclipse will be visible across parts of the southern hemisphere
• The Moon is New on Saturday
• The Sun currently has 3 active regions: AR2898, AR2899 and AR2900. The sunspot number is 53
• There are multiple visible evening ISS passes this week as follows:
  Monday: 17:40, W to E, max 84° and 19:16, W, max 17°
  Tuesday: 16:52, W to E, max 88° and 18:29, W, max 57°
  Wednesday: 17:42, W to ESE, max 87° and 19:19, W, max 16°
  Thursday: 16:55, W to E, max 86° and 18:32, W to SW, max 44°
  Friday: 17:44, W to SE max 61° and 19:22, W to WSW, max 13°
  Saturday: 16:57, W to ESE, max 75° and 18:34, W to SSW, max 25°
  Sunday: 17:47, W to SE, max 34°

Week of 22nd November

• Astronomical twilight ends at 18:08 GMT at the start of the week and at 18:04 GMT by the end of the week
• Five planets stretch across the ecliptic, starting in the West with Venus (mag -4.6), then Saturn (+0.7), Jupiter (-2.3), Neptune (+7.9) and in the East, Uranus (+5.7)
• Two dwarf planets are also in our sky: Pluto (+14.4) in the West and Ceres (+7.2) in the East in Taurus. Ceres reaches opposition on Saturday and is also at perigee, its closest point to Earth, making it appear at its brightest
• Comet C/2021 A1 (Leonard) is in our early morning sky, moving East between Ursa Major and Leo. It is currently at mag +8.5, but estimated to reach +7.4 by Sunday and brighter through early December. Could Leonard impress the early risers? It is highest in the sky before dawn at around 05:00 to 06:00 GMT. It is not in our sky for long as it moves south, below our horizon by mid December
• The Moon is Last Quarter on Saturday
• The Sun currently has 2 active regions: AR2896 and AR2897. The sunspot number is 22
• There are multiple visible evening ISS passes this week as follows:
  Monday: 16:46, SE, max 10° and 18:19, SW to S, max 39°
  Tuesday: 17:33, SSW to ESE, max 30° and 19:06, WSW, max 21°
  Wednesday: 16:46, SSW to E, max 22° and 18:22, WSW to SSW, max 66°
  Thursday: 17:35, WSW to E, max 55° and 19:11, W, max 20°
  Friday: 16:48, SW to E max 41° and 18:24, W, max 71°
  Saturday: 17:37, WSW to E, max 83° and 19:14, W, max 18°
  Sunday: 16:50, WSW to E, max 71° and 18:27, W to WNW, max 62°

Week of 15th November

• Astronomical twilight ends at 18:14 GMT at the start of the week and at 18:09 GMT by the end of the week
• On Tuesday there is a shadow transit of Ganymede across the disk of Jupiter (mag -2.4). The transit starts at 19:08 GMT and finishes at 22:36 GMT. Find Jupiter in the southwest at about 15° altitude
• Wednesday sees the peak of the Leonid meteor shower. The ZHR is around 15 meteors, but this will be impeded by the bright 98% full Moon. The shower is caused by debris deposited by comet 55P/Tempel-Tuttle
• On Friday morning there is a partial lunar eclipse; the Moon will enter the Earth’s penumbra at 06:03 GMT. Unfortunately, the majority of the eclipse will not be visible from Marlborough as the Moon sets at 07:31 GMT
• The Moon is Full on Friday
• The Sun currently has 3 active regions: AR2893, AR2894 and AR2895. The sunspot number is 24
• There are multiple visible evening ISS passes this week as follows:
  Friday: 19:08, SW to SSW, max 11°
  Saturday: 18:23, SSW to S, max 21°
  Sunday: 17:39, S to ESE, max 17° and 19:14, WSW to WSW, max 17°

Week of 8th November

• Astronomical twilight ends at 18:23 GMT at the start of the week and at 18:16 GMT by the end of the week
• The waxing Moon passes the planets through this week, making its close approach to Venus (mag -4.5) on Monday at sunset as a thin crescent, Saturn (+0.6) on Wednesday when 41% illuminated and Jupiter (-2.4) on Thursday when it will be First Quarter. On Saturday it will be near to Neptune (+7.9), but this pairing will be hard to spot, even in binoculars as the Moon will be 73% illuminated at mag -10.7
• Comet 67P/Churyumov-Gerasimenko, famous for the Rosetta mission and successful Philae lander in 2014, is at its brightest this week, though still only at mag +10. On Tuesday it is located about 2° below Pollux, heading southeast
• The Moon is First Quarter on Thursday
• The Sun currently has 3 active regions: AR2891, AR2893 and AR2894. The sunspot number is 41
• There are no visible evening ISS passes this week

Week of 1st November

• Astronomical twilight ends at 18:33 GMT at the start of the week and at 18:24 GMT by the end of the week
• Venus (mag -4.4) is visible close to the southwestern horizon around sunset, setting itself at about 18:30 GMT
• Saturn (+0.6) and Jupiter (-2.5) are in our southwestern evening sky. On Monday, Saturn sets at 22:21 GMT and Jupiter sets at 23:48 GMT
• Uranus (+5.7) is at opposition on Thursday. Find the planet in the southeast at an altitude of about 40°. You will need binoculars or a small telescope to see Uranus
• The Taurid meteor shower peaks on Thursday. It is a minor shower with a ZHR of only 5 to 10 meteors, but it can produce spectacular fireballs. Unusually, the shower is caused by two debris streams, the first from Asteroid 2004-TG10 and the second from Comet 2P/Enke
• The Moon is New on Thursday
• The Sun currently has 4 active regions: AR2887, AR2889, AR2891 and AR2892. There is a further active region emerging around the oncoming limb, as yet un-numbered. The sunspot number is 76
• There are no visible evening ISS passes this week

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°

Week of 27th September

• Astronomical twilight ends at 20:45 BST at the start of the week and at 20:31 BST by the end of the week
• Saturn (+0.5) and Jupiter (-2.7) continue to dominate our southern night sky and are perfectly placed for observation this week. Watch the transit of Jupiter’s moon, Io and its shadow on Wednesday evening; the transit commences at 18:55 BST and finishes at 21:15 BST
• The Moon is Last Quarter on Wednesday
• The Sun currently has 2 active regions: AR2871 and AR2872. The sunspot number is 38
• The ISS makes multiple visible evening passes this week as follows:
  Monday: 20:51, W to S, max 73°
  Tuesday: 20:03, W to ESE, max 86° & 21:40, W, max 20°
  Wednesday: 19:16, W to E, max 87° & 20:53, W to SSW, max 44°
  Thursday: 20:06, W to SE, max 58° & 21:43, W to WSW, max 12°
  Friday: 19:18, W to ESE, max 73° & 20:55, W to SSW, max 23°
  Saturday: 20:08, W to SSE, max 32°
  Sunday: 19:21, W to SE, max 43° & 20:59, WSW to SSW, max 11°

Week of 20th September

• Astronomical twilight ends at 21:03 BST at the start of the week and at 20:48 BST by the end of the week
• The Autumn Equinox occurs on Wednesday. At 20:21 BST the Sun will cross the Celestial Equator, heading south. This marks the start of autumn here in the Northern Hemisphere. There will be almost exactly 12 hours of night and day across our planet
• It is currently possible to spot five planets: Venus (mag -4.1) is setting low in our western evening sky, Saturn (+0.4) and Jupiter (-2.8) are high through the night, transiting at around 22:00 BST, Neptune (+7.8) follows further east and Uranus (+5.7) rises at 20:24 BST. For a sixth solar system planet, look to your feet to add Earth to the list!
• The Moon is Full on Tuesday – the Harvest Moon
• The Sun currently has 1 active region: AR2871. The sunspot number is 11
• The ISS makes multiple visible evening passes this week as follows:
  Monday: 19:54, SW to E, max 31° & 21:30, WSW, max 49°
  Tuesday: 20:43, WSW to E, max 72° & 22:20, W, max 14°
  Wednesday: 19:56, WSW to E, max 58° & 21:33, W, max 44°
  Thursday: 20:46, W to E, max 87° & 22:23, W, max 12°
  Friday: 19:59, WSW to E, max 86° & 21:36, W, max 35°
  Saturday: 20:49, W to E, max 87°
  Sunday: 20:02, W to E, max 84° & 21:39, W, max 27°

Week of 13th September

• Astronomical twilight ends at 21:22 BST at the start of the week and at 21:06 BST by the end of the week
• Neptune reaches opposition on Tuesday, when it will be opposite the Sun as seen from Earth. It will be best placed for observation, appearing at its brightest, though still faint at mag +7.8, so binoculars or a telescope will be needed to see the planet. Look southeast in the constellation of Aquarius through the evening
• Saturn (mag +0.4) and Jupiter (-2.8) continue to dominate our evening skies. They will be joined by the waxing Gibbous Moon towards the end of the week
• The Moon is First Quarter on Monday
• The Sun currently has 5 active regions: AR2863, AR2864, AR2866, AR2868 and AR2869. The sunspot number is 93
• The ISS makes multiple visible evening passes this week as follows:
  Thursday: 21:27, SW to SSW, max 14°
  Friday: 20:41, SSW to SSE, max 23°
  Saturday: 19:57, S to ESE, max 17° & 21:32, WSW to SW, max 31°
  Sunday: 20:47, SW to ESE, max 46°

Week of 6th September

• Astronomical twilight ends at 21:42 BST at the start of the week and at 21:25 BST by the end of the week
• On Thursday evening, spot the 3 day old waxing Crescent Moon just under 7° from Venus (mag -4.1) as they set in the West. Look just after sunset, which is at 19:34 BST
• Jupiter (-2.8) and Saturn (+0.3) are well placed in our evening skies
• With little to no moonlight, this week is the perfect opportunity to observe M27, the Dumbbell Nebula, a planetary nebula in the constellation of Vulpecula, just below Cygnus. At mag +7 and only 8 arcminutes in size, you will need a good pair of binoculars or a telescope to find it
• The Moon is New on Tuesday
• The Sun currently has 5 active regions, AR2863, AR2864, AR2865, AR2866 and AR2867. The sunspot number is 68
• There are no visible evening ISS passes this week

Week of 30th August

• Astronomical twilight ends at 22:03 BST at the start of the week and at 21:45 BST by the end of the week
• On Wednesday, Mercury (mag 0.0) reaches its highest point in the evening sky. It will be at 5° above the western horizon at sunset (19:52 BST). Take care of the setting Sun if searching for the planet, especially if using binoculars. Venus (-4.0) can be found 15° further East at about 9° altitude
• Saturn (mag +0.3) and Jupiter (-2.9) are well placed for observation in our evening sky this week, with Saturn culminating at 23:04 BST and Jupiter an hour later. To complete the suite of planets, find Neptune (+7.8) and  Uranus (+5.7) further East along the ecliptic
• The Moon is Last Quarter on Monday
• The Sun currently has 4 active regions, AR2859, AR2860, AR2861 and AR2862. The sunspot number is 77
• There are no visible evening ISS passes this week

Week of 23rd August

• Astronomical twilight ends at 22:24 BST at the start of the week and at 22:06 BST by the end of the week
• Venus makes a brief appearance in our western evening sky around sunset, shining at magnitude -4.0, but has set itself by 21:20 BST
• Four more planets are on view through the night, with, from West to East, Saturn (mag +0.3), followed by Jupiter (-2.9), then Neptune (+7.8) and finally Uranus (+5.7), which rises at 22:19 BST
• The Moon is waning Gibbous all week, not reaching Last Quarter until next Monday
• The Sun currently has 2 active regions, AR2858 and AR2859. The sunspot number is 25
• There are no visible evening ISS passes this week

Week of 16th August

• Astronomical twilight ends at 22:47 BST at the start of the week and at 22:28 BST by the end of the week
• Jupiter reaches opposition on Thursday. In this celestial position, opposite the Sun for us on Earth, it is best placed for observation, being at its brightest (mag -2.9) and largest with an apparent size of 49 arcseconds. This is the perfect time to train binoculars or a telescope on the Gas Giant, which you will find in the southeastern evening sky
• On Sunday, Jupiter rises at 20:06 BST in the east-southeast with a double moon transit in progress. Two of its Galilean moons, Europa and Ganymede, will be crossing in front of the planet and their shadows will also be visible on the planet’s surface. The event ends when Ganymede’s shadow leaves the disc at 23:20 BST
• The Moon is Full on Sunday – the Sturgeon Moon. It is the third of four Full Moons in the period from the summer solstice to the autumn equinox and as such, is called a Blue Moon
• The Sun currently has 4 active regions, AR2853, AR2855, AR2856 and AR2857. The sunspot number is 47
• There are no visible evening ISS passes this week

Week of 9th August

• Astronomical twilight ends at 23:11 BST at the start of the week and at 22:50 BST by the end of the week
• On Wednesday evening, the 3 day old waxing crescent Moon will make a close approach to Venus (mag -4.0), appearing with just 5° of separation low in the western sky just after sunset
• The Perseid meteor shower peaks on Thursday night, with a maximum zenithal hourly rate of around 150 meteors per hour, making it one of the most active showers of the year. The favourable Moon phase makes for optimum observing conditions through the night. The shower runs from 14th July to 24th August, so meteors can be spotted throughout that period. The shower is created by debris from comet 109P/Swift-Tuttle
• Saturn (+0.2) and Jupiter (-2.9) continue to adorn our evening skies in the southeast
• The Moon is First Quarter on Sunday
• The Sun currently has no active regions. The spotless stretch is 2 days
• There are no visible evening ISS passes this week

Week of 2nd August

• Astronomical twilight ends at 23:38 BST at the start of the week and at 23:15 BST by the end of the week
• Saturn reaches opposition on Monday, when it lies opposite the Sun in the sky. It is best placed for observation at this time as it appears at its largest and brightest at 18.6 arcseconds in apparent size and magnitude +0.2. At opposition, Saturn’s rings show a discernible brightening, known as the Seeliger Effect
• Jupiter is about 20° further East in the southeastern evening sky, shining at magnitude -2.8
• The Moon is New on Sunday
• The Sun currently has no active regions. The spotless stretch is 4 days
• There are no visible evening ISS passes this week

Week of 26th July

• Astronomical twilight ends at 00:15 BST at the start of the week and at 23:42 BST by the end of the week
• Look out for the waning Gibbous Moon in close proximity to Jupiter (mag -2.8) on Monday evening in the southeast
• The delta Aquarid meteor shower is active this week, with its peak on Wednesday. The bright Moon will reduce visibility to all but the brightest meteors. The shower has a max ZHR of 25 and its progenitor is comet P/2008 Y12 (SOHO)
• The Moon is Last Quarter on Saturday
• The Sun currently has two active regions, AR 2846 and 2847. The sunspot number is 35
• The ISS makes multiple evening passes this week as follows:
  Monday: 22:55, W to SW, max 33°
  Tuesday: 22:08, W to SE, max 45° and 23:46, WSW to SW, max 11°
  Wednesday: 22:58, W to SSW, max 17°
  Thursday: 22:10, W to SSE, max 24°

Week of 19th July

• Astronomical darkness returns this week as astronomical twilight ends at 00:55 BST on Wednesday and at 00:21 BST by the end of the week
• Venus (mag -3.9) and Mars (+1.8) are both visible in our evening sky throughout this week; look low to the western horizon just after sunset
• The Full Moon makes a close approach to Saturn (+0.2) on Saturday and Jupiter (-2.8) on Sunday. Look to the southeastern horizon to find the gas giants at around 23:00 BST
• The Moon is Full on Saturday – the Buck Moon, also known as the Hay Moon and the Thunder Moon
• The Sun currently has four active regions, AR 2842 in the northern hemisphere and 2843, 2844 & 2845 in the southern hemisphere. AR 2844 is a particularly rare high-latitude active region. The sunspot number is 53
• The ISS makes multiple evening passes this week as follows:
  Monday: 21:59, WSW to E, max 72° and 23:36, W to E, max 86°
  Tuesday: 22:49, W to E, max 84°
  Wednesday: 22:01, W to E, max 87° and 23:38, W to ESE, max 75°
  Thursday: 22:51, W to ESE, max 87°
  Friday: 22:04, W to E, max 86° and 23:40, W to S, max 45°
  Saturday: 22:53, W to SE, max 60°
  Sunday: 22:06, W to ESE, max 74° and 23:43, W to SW, max 24°

Week of 12th July

• Astronomical twilight does not end until 00:55 BST on 21st July
• On Monday, the shadow of Jupiter’s moon, Callisto, will transit the planet’s disk. The transit starts at 22:48 BST, before Jupiter rises at 22:55 BST, and ends at 03:32 BST.  The shadow will be visible just above the Great Red Spot
• Mercury is at its highest altitude in the morning sky on Tuesday. It rises at 03:43 BST, with sunrise at 05:05 BST. The planet (mag -0.4) will be 19° from the Sun and will reach a maximum visible altitude of 11°
• Tuesday’s evening sky features Venus (mag -3.9) and Mars (+1.8) making a close approach to each other. They will appear with just 29 arcminutes of separation. Look to the western horizon soon after sunset (21:19 BST)
• On Friday night it will be possible to spot the clair-obscur effects that produce the Lunar ‘V’ and ‘X’ at the Moon’s terminator. Look at around 22:45 BST with binoculars as the Moon approaches the western horizon
• The Moon is First Quarter on Saturday
• The Sun currently has two active regions, AR 2841 and AR 2842. The sunspot number is 24
• The ISS makes multiple evening passes this week as follows:
  Monday: 22:41, S to ESE, max 16°
  Tuesday: 23:29, SW to E, max 42°
  Wednesday: 22:42, SSW to E, max 31°
  Thursday: 23:31, WSW to E, max 71°
  Friday: 22:44, WSW to E, max 56°
  Saturday: 21:57, SW to E, max 42° and 23:34, W to E, max 87°
  Sunday: 22:46, WSW to E, max 84°

Week of 5th July

• Astronomical twilight does not end until 00:55 BST on 21st July
• The Earth reaches aphelion on Monday, when it will be at its most distant point from the Sun in its annual orbit. There will be 1.02 AU or 152,100,527 km, between the Earth and the Sun
• Venus (mag -3.9) and Mars (1.8) continue to feature in our evening sky. Look just a few degrees above the western horizon after sunset at around 21:30 BST to find the pair
• The waning Moon means dark skies this week, the perfect time to search in and around the Summer Triangle for fainter objects such as M57, the Ring Nebula in Lyra. Binoculars or a telescope will be required
• The Moon is New on Saturday
• The Sun currently has four active regions, AR 2835, AR 2386, AR 2387 and AR 2388. The sunspot number is 81
• The ISS returns to our evening sky this week with one visible pass:
  Sunday: 23:31, ESE to E, max 18°

Week of 28th June

• Astronomical twilight does not end until 00:55 BST on 21st July
• Watch the planets Venus (mag -3.9) and Mars (+1.8) appear ever closer to eachother through this week in our evening sky. Look to the western horizon to see the pair just after sunset
• The waning gibbous Moon passes by both Saturn (mag +0.4) and Jupiter (-2.6) on Monday and Tuesday. Look southeast, just above the horizon around 00:00 BST to see the solar system objects
• Mercury reaches greatest elongation west on Sunday, appearing with 21.6° separation from the Sun in the morning sky just before sunrise
• The Moon is Last Quarter on Thursday
• The Sun currently has one active region, AR 2835. The sunspot number is 16
• There are no visible evening ISS passes this week

Week of 21st June

• Astronomical twilight does not end until 00:55 BST on 21st July
• The Summer Solstice occurs at 04:25 BST on Monday, when the Sun will be at its most Northerly point in the sky with a declination of +23.5°. It will have an altitude of 62° at 13:00 BST, its highest point in the sky of the year. Monday will be the longest day of the year for us in the Northern Hemisphere and Monday night the shortest night, with only 7 hours 21 minutes between sunset and sunrise. The rising and setting of the Sun are also at their most northerly point of the year, with sunrise on Monday happening at an azimuth of just 49°, compare this with sunrise on the Winter Solstice at an azimuth of 128°!
• On Wednesday, Mars (mag +1.8) will be in conjunction with M44 the Beehive Cluster in Cancer. Look to the north-northwest horizon after sunset to find the planet and cluster. Venus (-3.9) will be just a few degrees further west
• The Moon is Full on Thursday – the Strawberry Moon (nothing to do with its colour, but so named as it indicates the time of year to gather ripening fruit)
• The Sun currently has one active region, AR 2833. The sunspot number is 15
• There are no visible evening ISS passes this week

Week of 14th June

• Astronomical twilight does not end until 00:55 BST on 21st July
• The Milky Way is well placed for observation this week as it rises higher in our evening sky. Use a pair of binoculars to take in the wealth of stars and dusty regions along the visible disc of our galaxy. Try to find the ‘Coathanger’ asterism in Vulpecula by first locating the wonderful double star Albireo, the beak of Cygnus, and then move a few degrees southwest to spot the upside down coathanger pattern of stars
• The gas giants Saturn and Jupiter are returning to our evening skies now, with Saturn rising at 23:57 BST at magnitude +0.5 and Jupiter following a little later at 00:42 BST, shining at mag -2.5
• The Moon is First Quarter on Friday
• The Sun currently has one active region, AR 2833, emerging around the oncoming mid-latitude northern hemisphere limb
• There are no visible evening ISS passes this week

Week of 7th June

• Astronomical twilight does not end until 00:55 BST on 21st July
• There is a solar eclipse on Thursday, appearing as an annular eclipse to those in Canada and Greenland, while it will be a partial eclipse for us here in Marlborough. First contact is at 10:06 BST, with maximum eclipse at 11:11 BST, when about 21% of the Sun will be obscured by the Moon. Last contact is at 12:20 BST. Hopefully the weather will allow a live stream to be broadcast. Take great care if trying to observe the partial eclipse yourself
• The Arietid meteor shower peaks on Thursday at around 15:00 BST. This is during daylight hours, so whilst meteors won’t be seen by eye, the radio meteor detector should see an increase in activity – watch the live stream to observe meteors in broad daylight!
• The Moon is New on Thursday
• The Sun currently has two active regions, AR 2827 and AR 2829. The sunspot number is 30. There has been a significant increase in solar activity so far this year, with only 29% of days being spotless. Compare this with 57% spotless days in 2020 and 77% spotless days in 2019
• There are no visible evening ISS passes this week

Week of 31st May

• Astronomical twilight does not end until 00:55 BST on 21st July
• This week’s challenge is to hunt down the array of Globular Clusters above the arc of the Milky Way. These include M3 (in Bootes), M13 (the Great Hercules Cluster) and M92 (in Hercules), M5 (in Serpens) and M10 and M14 (in Ophiuchus). Binoculars or a small telescope will suffice to spot these magnificent balls of stars
• The Moon is Last Quarter on Wednesday
• The Sun currently has two active regions, AR 2824 (off going) and AR 2827 (a new on coming region). The sunspot number is 26
• There are no visible evening ISS passes this week

Week of 24th May

• Astronomical twilight does not end until 00:55 BST on 21st July
• Noctilucent cloud season starts around now, so keep an eye out near the northern horizon around 90 minutes after sunset to try and spot these beautiful, high level night shining, opalescent clouds
• There is a total lunar eclipse on Wednesday. Unfortunately, it is not visible from the UK, but only visible from Oceania, the Americas and Eastern and Southeast Asia
• The Moon is Full on Wednesday – the Flower Moon. As the Moon will be very close to perigee, this will make it a ‘supermoon’. It will be the largest and brightest full Moon of 2021
• The Sun currently has one active region, AR 2824. The sunspot number is 19
• The ISS makes the following visible evening passes this week:
  Monday: 21:58, W to E, max 89° and 23:35, W to S, max 49°
  Tuesday: 22:48, W to SE, max 53°
  Wednesday: 22:00, W to ESE, max 68° and 23:37, W to SSW, max 21°
  Thursday: 22:49, W to SSE, max 29°
  Friday: 22:02, W to SE, max 39°
  Saturday: 22:52, WSW to SSW, max 15°
  Sunday: 22:04, W to SSE, max 21°

Week of 17th May

• Astronomical twilight ends at 00:02 BST at the beginning of the week, but by the end of the week, here at a latitude of 51° North, the Sun will no longer sink more than 18° below the horizon, meaning that astronomical twilight does not end. We will not experience astronomical darkness again until the 21st July
• Mercury reaches greatest elongation east this week on Monday, placing it at its greatest separation from the Sun. Look for the planet low to the west-northwestern horizon just after sunset
• The waxing Moon provides a good target this week, where plenty of surface detail can be observed, especially along the Terminator – the line separating night and day on the Moon
• The Moon is First Quarter on Wednesday
• The Sun currently has two active regions, AR 2822 and AR 2823. The sunspot number is 24
• The ISS makes the following visible evening passes this week:
  Monday: 22:40, WSW to E, max 64°
  Tuesday: 21:56, SW to E, max 49° and 23:29, W to E, max 85°
  Wednesday: 22:41, W to E, max 89°
  Thursday: 21:54, WSW to E, max 78° and 23:31, W to E, max 89°
  Friday: 22:43, W to E, max 84°
  Saturday: 21:56, W to E, max 85° and 23:33, W to ESE, max 68°
  Sunday: 22:45, W to ESE, max 82°

Week of 10th May

• Astronomical twilight ends at 23:34 BST at the beginning of the week and at 00:02 BST by the end of the week
• On Thursday, the very thin, 1.8 days old, waxing Crescent Moon will be in conjunction with Mercury (mag +0.1), separated by about 2.5°. Look at around 14° altitude above the west-northwest horizon at about 21:00 BST, after sunset. You will also find Venus (-3.9) lower down, just above the horizon
• On Sunday, Mercury will reach its highest point in the sky for this apparition, sitting at an altitude of 16° at 21:00 BST
• The Moon is New on Tuesday
• The Sun currently has one active region, AR 2822. The sunspot number is 17
• The ISS makes the following visible evening passes this week:
  Friday: 21:51, SSE to ESE, max 13° and 23:25, SW to E, max 49°
  Saturday: 22:38, SW to E, max 36°
  Sunday: 21:51, SSW to E, max 26° and 23:27, WSW to E, max 78°

Week of 3rd May

• Astronomical twilight ends at 23:07 BST at the beginning of the week and at 23:30 BST by the end of the week
• The Eta-Aquariid meteor shower peaks on Thursday. Best prospects for observing inceased meteor numbers are in the early pre-dawn hours, when the Zenithal Hourly Rate is expected to be around 30-40. This meteor shower is created by debris deposited by comet 1P/Halley
• Mercury appears low to the northwestern horizon shortly after sunset this week. On Tuesday, look at an altitude of about 9° and azimuth of 290° at around 21:15 BST, to find the planet shining at mag -0.8 just to the east of the Pleiades (+1.5). Take great care to avoid the glare of the Sun when looking for Mercury at sunset
• At the start of the week the Waning Moon will appear in close proximity to Saturn (mag +0.7) and Jupiter (-2.2) in the southeastern pre-dawn sky
• The Moon is Last Quarter on Monday
• The Sun currently has one active region, AR 2818 and one emerging region on the oncoming limb that may develop into an active regtion. The sunspot number is 11
• There are no visible ISS evening passes this week

Week of 26th April

• Astronomical twilight ends at 22:44 BST at the beginning of the week and at 23:04 BST by the end of the week
• On Tuesday the Moon reaches perigee, the closest point to Earth along its orbit. It will be at a distance of about 357,000 km with an angular size of 33.42 arcminutes, compared to its average size of 31.07 arcminutes. Perigee coincides with the full Moon, making it a ‘super Moon’, the first of three this year
• The Moon is Full on Tuesday – the Super Pink Moon. Named ‘Super’ as it is a super Moon and ‘Pink’ after the early seasonal arrival of a species of wildflower in northern Native American culture
• The Sun currently has multiple active regions, AR 2816, 2818, 2819 and 2820. The sunspot number is 62. There is a significant increase in activity so far this year compared to 2020
• There are no visible ISS evening passes this week

Week of 19th April

• Astronomical twilight ends at 22:24 BST at the beginning of the week and at 22:41 BST by the end of the week
• The Lyrid meteor shower peaks on Thursday afternoon. Look out for increased meteor activity on both Wednesday and Thursday nights. The predicted Zenithal Hourly Rate is only 18, so don’t expect an intense display and viewing will be further hampered by the waxing Gibbous Moon. Hopefully the Radio Meteor Detector will pick up the increased activity. The Lyrid meteors are created by debris left behind by comet C/1861 G1 (Thatcher)
• The Moon is First Quarter on Tuesday
• The Sun currently has two active regions, AR 2814 and AR 2816. The sunspot number is 28. Recent data on sunspot count and solar activity suggest that the new Solar Cycle 25 is intensifying more quickly than originally predicted and the peak could be in 2024 rather than 2025
• There are no visible ISS evening passes this week

Week of 12th April

• Astronomical twilight ends at 22:05 BST at the beginning of the week and at 22:21 BST by the end of the week
• On Saturday the 27% waxing Crescent Moon will appear close to Mars, with a separation of just under 4°. Look in the West after sunset to find the pair
• The Moon is New on Monday
• The Sun currently has no visible active regions. The spotless stretch is 4 days
• There are no visible ISS evening passes this week

Week of 5th April

• Astronomical twilight ends at 21:48 BST at the beginning of the week and at 22:03 BST by the end of the week
• For the early risers, look low to the southeastern horizon from around 05:30 BST for about an hour before sunrise to find the waning Crescent Moon. On Tuesday morning it will be in conjunction with Saturn (mag +0.8) and on Wednesday morning it will be in conjunction with Jupiter (-2.1)
• The Moon is a waning Crescent all this week
• The Sun has one emerging potential active region in the Northern Hemisphere. It has been increasingly active so far this year, with only 36 spotless days, that being 38%; compare this to 57% spotless days last year and 77% the year before
• There are no visible ISS evening passes this week