July 2020 What’s Up!

Week of 27th July

  • Astronomical twilight ends at 00:08 BST at the beginning of the week and at 23:37 BST by the end of the week
  • Goodbye Comet NEOWISE (C/2020 F3)! The comet passed perigee on the 23rd and is now travelling away from both the Earth and Sun. It is fading and has dropped to about mag +3. This, along with the waxing Moon, will make it increasingly difficult to spot. This comet is not due to return to our skies for about 6,800 years. For a last look, find the comet after sunset in the northwest below the Plough
  • The Southern Delta Aquariid meteor shower peaks on Wednesday night. However, with only about 25 meteors per hour at its peak, which will reduce to around just 9 visible per hour due to the bright Moon, this is unlikely to be a particularly spectacular shower. The radiant is in Aquarius and the parent body responsible for the shower is thought to be comet P/2008 Y12 (SOHO)
  • Jupiter (-2.7) and Saturn (+0.1) continue to shine brightly in our southern evening sky. The pair are joined by a 97% waxing Moon on Saturday, when Jupiter will lie just 2° above the Moon
  • Mercury reaches its highest point in the morning sky on Monday. At sunrise, 05:24 BST, it will be at an altitude of 12° in the East. Take great care to avoid the Sun if trying to observe this event
  • The Moon will be at First Quarter on Monday
  • The Sun has one active region, AR 2767, in a high southerly latitude belonging to new Solar Cycle 25
  • The ISS makes visible evening passes this week as follows:
    Monday – 21:42, W to ESE, max 73° & 23:19, W to SSW, max 23°
    Tuesday – 22:31, W to SSE, max 32°
    Wednesday – 21:43, W to SE, max 44° & 23:21, WSW to SW, max 11°
    Thursday – 22:32, W to S, max 17°
    Friday – 21:44, W to SSE, max 24°
    Sunday – 21:46, WSW to SSW, max 12°

Week of 20th July

  • This week sees the return of astronomical darkness. On Monday night, starting at 00:51 BST, we will enjoy 54 minutes of ‘proper’ darkness. By Sunday, astronomical twilight will end at 00:14 BST, with astronomical darkness lasting for two hours
  • Comet NEOWISE (C/2020 F3) continues to put on a fabulous display, though it is now starting to dim as it travels away from the Sun. It is best viewed in the evening sky, at 23:00 BST it is at an altitude of about 20° above the northwestern horizon. At the start of the week it is sitting around 15° below the Plough, by the front paw of the Great Bear, by the end of the week it will have moved West to sit behind the Bear’s back paw. Whilst it is still visible with the naked eye, the best views are gained with binoculars
  • Jupiter and Saturn make excellent evening targets in the southeastern sky this week. They are low to the horizon at an altitude of about 12°. Jupiter is mag -2.7 and Saturn is mag +0.1. Saturn reaches opposition on Monday, meaning it lies opposite the Sun from Earth and is best placed for the largest and brightest views. Look out for the transit of Jupiter’s moon Callisto on Saturday night, it moves across the gas giant’s disk from 22:55 BST until 03:00 BST on Sunday morning
  • Mercury is at Greatest Elongation West on Wednesday and will be visible at about 05:00 BST, just before sunrise, in the northeast at an altitude of about 9° shining at around mag +0.5. Venus is also a morning object, rising at around 02:30 BST and shining as the bright ‘morning star’ at mag -4.4
  • The Moon is New on Monday
  • The Sun has no active regions, with the current spotless stretch at 8 days
  • The ISS makes visible evening passes as follows:
    Monday – 22:27, W to E, max 87°
    Tuesday – 23:16, W to E, max 87°
    Wednesday – 22:28, W to E, max 84°
    Thursday – 23:17, W to ESE, max 72°
    Friday – 22:29, W to ESE, max 85°
    Saturday – 23:17, W to SSE, max 44°
    Sunday – 22:29, W to SE, max 58°

Week of 13th July

  • Astronomical twilight does not end until 21st July
  • Comet NEOWISE (C/2020 F3) is the finest comet to appear in our skies for many years. It is now circumpolar and is visible from sunset to sunrise. However, it is very low to the northern horizon, so you need to choose your observing location accordingly. Through the week it increasingly becomes an evening object. It is at 10° altitude and 338° azimuth at 23:00 BST on Monday evening, moving to 8° alt, 10° az by 02:00 BST that night. By Friday, it is at 16° alt, 330° az, at 23:00 BST and 9° alt, 359° az, at 02:00 BST on Saturday morning. This is a must see object, let’s hope for clear skies!
  • The planets make an impressive line up across the southern sky this week. Jupiter (mag -2.8) reaches opposition on Tuesday, it is also at perigee, making this the best time to observe Jupiter at its largest and brightest in our sky. It is visible along with Saturn (mag 0.1) at an altitude of around 14° above the southeastern horizon throughout the evening. For the night owls and early risers, Mars appears above the eastern horizon after midnight, followed by Venus, which rises in the northeast at about 02:45 BST. The waning crescent Moon rises within 3° of Venus on Friday morning and will make an impressive sight
  • The Moon is waning and starts the week at Last Quarter on Monday
  • The Sun currently has no active regions
  • The ISS is visible in our skies again with evening passes as follows:
    Monday – 23:13, SSW to E, max 25°
    Tuesday – 22:26, S to E, max 18°
    Wednesday – 23:13, 23:13, SW to E, max 47°
    Thursday – 22:26, SW to E, max 34°
    Friday – 23:14, WSW to E, max 76°
    Saturday – 22:26, WSW to E, max 61°
    Sunday – 23:15, W to E, max 86°

Week of 6th July

  • Astronomical twilight does not end until 21st July
  • The Gas Giants, Jupiter and Saturn, are visible in the southeastern evening sky, with Jupiter rising at 21:41 BST and Saturn following close behind at 22:00 BST. Jupiter appears at about mag -3, while Saturn is some 16 times dimmer at mag 0. Watch as the Full Moon forms a right angle triangle with the two planets on Sunday night into Monday morning. Jupiter and Saturn both reach opposition later this month
  • Mars is starting to appear in our night sky, rising at around 00:30 BST. The best views will be later in the year as it reaches opposition in October
  • Venus continues to grace our morning skies, rising at around 03:00 BST and shining at mag -4.5 towards the northeast in the Hyades
  • The Moon is Waning Gibbous all week
  • The Sun has one small active region near its equator. The low latitude and magnetic polarity identify it as a member of the old Cycle 24, which still has a bit of life in it yet
  • There are no ISS evening passes visible this week