July 2024 – What’s Up!

Week of 29th July

• Astronomical twilight ends at 23:54 BST at the start of the week and at 23:29 BST by the end of the week.
• The Delta Aquariid meteor shower is active through this week. It has a peak ZHR of about 25. The shower’s progenitor is comet P/2008 Y12 (SOHO).
• Dark, Moon free skies are perfect for the continuing exploration of the Summer Triangle. This week, hunt around the southern tip for an asterism, a cluster and a planetary nebula. Start with Brocchi’s Cluster (+3.6), Collinder 399 in Vulpecula, a fascinating asterism that looks like an upside down coathanger! Then down to M71 (+8.2) a globular cluster in Sagitta. Finally, return to Vulpecula for M27 – the Dumbbell Nebula (+7.1), a wonderful planetary nebula also know as the Apple Core Nebula, a name which makes sense when the nebula is viewed through the eyepiece!
• The Moon is New on Sunday.
• The Sun currently has 10 active regions and the sunspot number is 178.
• There are no visible evening ISS passes this week (click here for full ISS pass details).

Week of 22nd July

• Astronomical twilight ends at 00:41 BST at the start of the week and at 23:59 by the end of the week.
• Mercury (+0.5) reaches Greatest Eastern Elongation on Monday. It will be quite hard to spot at just 6° altitude above the western horizon at sunset. Take care of the Sun if hunting for Mercury with binoculars.
• The Waning Gibbous Moon makes a close approach to Saturn (+0.9) on Thursday. The pair will rise together at about 23:00 BST.
• Three interesting targets reside in Lyra to search out with a telescope this week: the Double Double – Epsilon Lyrae (+5.0), The Ring Nebula – M57 (+8.8), and Globular Cluster – M56 (+8.3).
• The Moon is Last Quarter on Sunday.
• The Sun currently has 13 active regions and the sunspot number is 212.
• 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 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).