May 2023 – What’s Up!

Week of 29th May

• Astronomical twilight does not end until July 21st.
• Venus (mag -4.3) reaches Greatest Eastern Elongation on Sunday, when it will be at its furthest separation from the Sun. It is the brightest object (apart from the Moon and Sun!) in the west at sunset and is about 30° above the horizon.
• SN 2023ixf is a new supernova in the galaxy M101 in Ursa Major, about 5° above Alkaid, the star at the end of the Saucepan’s handle. Discovered on 19th May 2023, it is still at peak brightness of about +11, but is expected to start to dim soon and fade away over the coming weeks. It should just be visible in a telescope.
• The Moon is Full on Sunday – the Strawberry Moon.
• The Sun currently has 7 active regions and the sunspot number is 125.
• There are no 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 22nd May

• Astronomical twilight ends at 00:47 BST at the beginning of the week, but from Wednesday onwards, astronomical twilight does not end until July 21st. This is because the Sun does not sink more than 18° below the northern horizon.
• The waxing Crescent Moon will pass by Venus (mag -4.2) on Tuesday and Mars (+1.5) on Wednesday in the western evening sky.
• Despite the temporary end of astronomical darkness, it is still dark enough to observe, though you can’t really start your session until around 23:00 BST. This week we are searching for three galaxies around The Plough. First is M51, the Whirlpool Galaxy (+7.9) a few degrees below the end of ‘the handle’, next is M81, Bode’s Nebula (+6.8) and finally, close neighbour M82, the Cigar Galaxy (+8.0), which are both above and west of ‘the pan’. The most distant is M51 at 28 million light years!
• The Moon is First Quarter on Saturday.
• The Sun currently has 8 active regions and the sunspot number is 138.
• There are multiple visible evening ISS passes this week. Click this link to see full details on the heavens-above website: heavens-above-iss-passes. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings.

Week of 15th May

• Astronomical twilight ends at 23:55 BST at the beginning of the week and at 00:34 BST by the end of the week.
• There is a close approach of the Waning Crescent Moon and Jupiter (mag -2.1) on Wednesday afternoon. **Take extreme care of the Sun if trying to spot this conjunction with binoculars or a telescope**. The two objects will be closest at about 15:05 BST. Look at an altitude of around 28° above the western horizon. From more northerly latitudes this will appear as a lunar occultation of Jupiter.
• Venus (-4.2) will be at an altitude of 32° in the west at sunset, around 21:00 BST, throughout this week.
• The New Moon makes conditions ideal for this week’s Deep Sky Challenge, which is a hunt for three globular clusters. First up is M3 (+6.2) in Canes Venatici, next slew south to Serpens to find M5 (+5.6) and finally west to find M13 (+5.8), the spectacular Great Hercules Cluster in Hercules. Good luck with your hunt!
• The Moon is New on Friday.
• The Sun currently has 9 active regions and the sunspot number is 120.
• There are multiple visible evening ISS passes this week. Click this link to see full details on the heavens-above website: heavens-above-iss-passes. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings.

Week of 8th May

• Astronomical twilight ends at 23:24 BST at the beginning of the week and at 23:50 BST by the end of the week.
• Venus has brightened slightly to magnitude -4.2 as it moves closer to Earth and increases in apparent size. It now appears about 18 arcseconds across and is at a distance of 0.9 AU. Look to the west in the evening sky to spot the ‘evening star’.
• With the Waning Moon this week, darker skies allow fainter deep sky object hunting. This week’s challenge is the planetary Nebula M97, the Owl Nebula in Ursa Major. Located under the saucepan, close to the star Merak, it is a small and faint object at magnitude +9.8 and just 3.4 arcminutes in apparent size. You will need a telescope to spot the darker ‘eyes’ that give the nebulous remains of this exploded star its name.
• The Moon is Last Quarter on Friday.
• The Sun currently has 5 active regions and the sunspot number is 99.
• There are multiple visible evening ISS passes this week. Click this link to see full details on the heavens-above website: heavens-above-iss-passes. If you are not in Marlborough, please ensure that you set your location for the most accurate ISS timings.

Week of 1st May

• Astronomical twilight ends at 22:59 BST at the beginning of the week and at 23:20 BST by the end of the week.
• Venus (mag -4.1) continues to dominate our evening sky in the west. Its waxing gibbous phase should be clearly visible in a small telescope.
• The Eta Aquariid meteor shower peaks on Friday, but the Full Moon will drown out all but the very brightest meteors in visible wavelengths. Follow the Radio Meteor Detector live feed for your best chance to see a meteor. The parent body responsible for this shower is comet 1P/Halley.
• The Moon is Full on Friday – the Flower Moon.
• The Sun currently has 5 active regions and the sunspot number is 82.
• There are no visible evening ISS passes this week.