July 2024 – What’s Up!

Week of 15th July

  • Astronomical darkness returns at the end of this week when astronomical twilight finally ends on Sunday morning at 00:51 BST; it starts again at 01:36 BST, giving us 45 minutes of true astronomical darkness!
  • Look out for a group of up to 20 Starlink satellites which are expected to deorbit in the coming days following a failed launch on 11th July. If we are lucky enough to witness this event, we can expect to see multiple slow moving meteor-like trails across the sky.
  • Early risers can enjoy the planets this week and a conjunction of Uranus and Mars on Monday and Tuesday. Look in the south through to the east at around 04:30 BST to find the line up of: Saturn (+1.0), Neptune (+7.9), Mars (+0.9), Uranus (+5.8) and Jupiter (-2.1).
  • Mercury (+0.2) and Venus (-3.9) are evening objects, though Venus is currently too close to the Sun for safe observation.
  • The Moon is Full on Sunday – the Buck Moon.
  • The Sun currently has 11 active regions and the sunspot number is 214.
  • There are multiple visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).

Week of 8th July

  • Astronomical twilight does not end until 21st July.
  • Mercury reaches its highest altitude in the evening sky on Tuesday, reaching about 10° above the western horizon just after sunset at 21:20 BST. CAUTION: Avoid the Sun if trying to spot Mercury with binoculars or a telescope!
  • Bag four Messier Globular Clusters with your telescope this week, but only if you have a very good low view of the southern horizon. Find the bright Red Giant star, Antares (Alpha Scorpii, mag +1.1) in the south, look about one degree west to find M4 (+5.6). Next, head northwest four degrees to M80 (+7.3), then east ten degrees to M19 (+6.8), and finally, four degrees south to M62 (+6.4), the lowest of the four globs at just 8° above the southern horizon.
  • The Moon is First Quarter on Saturday.
  • The Sun currently has 9 active regions and the sunspot number is 132.
  • There are multiple visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).

Week of 1st July

  • Astronomical twilight does not end until 21st July.
  • Earth reaches aphelion on Friday when it will be at the most distant point from the Sun in its orbit, at a distance of 1.0167 AU. A common misconception is that our seasons come about from Earth’s changing distance from the Sun, but that is all to do with the tilt of Earth’s axis and whether we are tilted towards or away from the Sun. However, it does mean that the Southern Hemisphere’s summers are a bit hotter as they coincide with perihelion, Earth’s closest point to the Sun in its orbit, which happens two weeks after the December Solstice.
  • This week’s New Moon gives perfect sky conditions for spotting fainter deep sky objects; see if you can find three small and faint planetary nebulae in and around the Summer Triangle. First up is M57, the Ring Nebula in Lyra at magnitude +8.8. Next to Vulpecula for M27, the Dumbbell Nebula (+7.1), and finally to Cygnus for NGC 6826, the Blinking Planetary Nebula (+8.9), so named because with direct vision, the nebula fades away as the bright central star overwhelms, then if you look away, averted vision causes the nebula to reappear, giving the impression of ‘blinking’!
  • The Moon is New on Friday.
  • The Sun currently has 15 active regions and the sunspot number is 205.
  • There are multiple visible evening ISS passes this week.
    (For full details about ISS passes click this link: heavens-above-iss-passes to visit the heavens-above website. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings).