May 2020 What’s Up!

Week of 25th May

  • Astronomical twilight does not end until 21st July as the Sun does not sink lower than 18° below the horizon
  • Mercury reaches its highest point in the evening sky on Sunday. Look to the northwest in the hour after sunset to see Mercury climb ever higher this week
  • Comet C/2020 F8 (SWAN) reaches perihelion on Friday. Look to 18° altitude above the northwestern horizon at around 10pm BST. It is about mag +6, on the border of naked eye visibility, but given its low altitude and the lack of darkness, binoculars will be required
  • On Wednesday evening at 9.32pm BST you should be able to watch the NASA/SpaceX Demo-2 live launch online. The first launch from US soil to the ISS since 2011
  • Binocular Deep Sky Target of the Week: M13, The Great Hercules Cluster. This globular cluster is the brightest in the Northern Hemisphere sky and is easily visible in binoculars at mag +5.8. Look on the western side of the Keystone asterism in the constellation of Hercules. It lies about 25,000 light years away and contains some 300,000 stars
  • The Moon is waxing and will be First Quarter on Saturday
  • The Sun has no active regions, with the current spotless stretch at 22 days
  • The ISS makes the following evening passes this week:
    Monday: 22:55, W to ESE, max 62°
    Tuesday: 22:07, W to ESE, max 76° and 23:44, W to SSW, max 25°
    Wednesday: 22:57, W to SSE, max 35°
    Thursday: 22:09, W to SE, max 47° and 23:46, WSW to SW, max 13°
    Friday: 22:58, W to S, max 18°
    Saturday: 22:10, W to SSE, max 26°

Week of 18th May

  • Astronomical twilight ends at 00:16 BST at the start of the week. From Saturday, Astronomical Twilight does not end until 21st July as the Sun never sinks lower than 18° below the horizon
  • Mercury starts to climb into the western evening sky. On Thursday and Friday it is in conjunction with Venus, separated by less than 2° (Be careful of the setting Sun if you attempt to spot Mercury with binoculars)
  • Comet C/2020 F8 (SWAN) is now low in the northern horizon and is at around mag +6
  • The Moon is waning and will be New on Friday
  • The Sun has no active regions, with the current spotless stretch at 14 days
  • The ISS makes multiple bright evening passes this week as follows:
    Monday: 22:03, SW to E, max 42° and 23:40, W to E, max 87°
    Tuesday: 22:52, WSW to E, max 84°
    Wednesday: 00:29, W to ESE, max 87°, 22:04, WSW to E, max 71° and 23:41, W to E, max 86°
    Thursday: 22:53, W to E, max 84°
    Friday: 00:30, W to S, max 61°, 22:05, W to E, max 88° and 23:42, W to ESE, max 76°
    Saturday: 22:54, W to E, max 88°
    Sunday: 00:31, W to SW, max 31°, 22:06, W to E, max 86° and 23:43, W to SSE, max 47°

Week of 11th May

  • Astronomical twilight ends at 23:39 BST at the start of the week and 00:09 BST at the end
  • Venus is appearing to change rapidly as it moves towards inferior conjunction; it starts the week as a 15% crescent and finishes at 10%. It is increasing in apparent size and will appear about 50 arcseconds by the end of the week. For comparison, at the end of 2019 it appeared only about 12 arcseconds in size
  • Comet C/2017 T2 (PANSTARRS) is expected to be at its brightest on Wednesday as it moves through Camelopardalis towards Ursa Major. It is a binocular target at around mag +8
  • Comet C/2020 F8 (SWAN) will become visible low to the northeastern horizon in our morning sky from the middle of the week. It has been exciting observers in the Southern Hemisphere as it is on the border of naked eye visibility at mag +6 and has a very elongated tail. It will be fascinating to watch how this comet develops over the coming weeks
  • The Moon is waning and will be Last Quarter on Thursday
  • The Sun has no active regions, with the current spotless stretch at 8 days
  • The ISS returns to our evening sky this week with passes as follows:
    Friday: 22:50, SW to E, max 31°
    Saturday: 22:03, SSW to E, max 23° and 23:38, WSW to E, max 72°
    Sunday: 22:51, WSW to E, max 57°

Week of 4th May

  • Astronomical twilight ends at 23:12 BST at the start of the week and 23:35 BST at the end
  • While Comet C/2019 Y4 (ATLAS) may have disappointed by breaking up, comets C/2017 T2 (PANSTARRS) and C/2020 F8 (SWAN) may give observers something to enjoy. PANSTARRS reaches perihelion on Tuesday and is well placed in Camelopardalis; however, at mag +8, binoculars or a telescope will be needed. Comet SWAN is not visible in the Northern Hemisphere yet, but should appear in our skies towards the end of May
  • Venus will appear in its crescent phase this week, shining brightly at mag -4.5 in the western evening sky
  • The Eta Aquarid meteor shower peaks on Wednesday, though the Full Moon will drown out the majority of meteors. The shower is a result of the Earth passing through the stream of debris deposited by Halley’s Comet
  • The Moon will be Full on Thursday. This will be the ‘Flower Moon’, the fourth and last supermoon of the year
  • The Sun has no active regions, with the current spotless stretch at 2 days
  • There are no visible evening ISS passes this week
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