June 2023 – What’s Up!

Week of 26th June

  • Astronomical twilight does not end until July 21st.
  • Venus (mag -4.4) is conspicuous in the west around sunset. Use a telescope to see its waning crescent phase. If you follow it over the coming weeks, you will see it increase in apparent size as it approaches Earth in its orbit.
  • The final observing challenge of June is to use a pair of binoculars to explore the Milky Way. Take your time to navigate the myriad stars interspersed with dark nebulous patches. Can you find Brocchi’s Cluster, also called the Coathanger due to the particular shape formed by its stars? Look about two thirds of the way from Vega to Altair in the Summer Triangle.
  • The Moon is First Quarter on Monday.
  • The Sun currently has 14 active regions and the sunspot number is 200.
  • 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 19th June

  • Astronomical twilight does not end until July 21st.
  • On Wednesday, at 15:54 BST the Sun will reach its maximum declination of +23.5°, creating the longest day and the Summer Solstice here in the northern hemisphere. It is historically important as Eratosthenes observed the difference in altitude of the Sun from Aswan and Alexandria in Egypt on the Summer Solstice in about 240 BC to be the first to calculate the circumference of the Earth.
  • Spot the thin crescent Moon (mag -4.8) close to bright Venus (-4.4) on Wednesday evening. Look above the western horizon around sunset to see the pair.
  • This week’s observing challenge involves double stars in the Summer Triangle: start with Albireo in Cygnus, a beautiful contrasting colour pair at mag +3.1. Then move your telescope to Epsilon Lyrae (+5.0), better known as the Double Double, which will require good seeing and high magnification to successfully split all four stars.
  • The Moon is Waxing Crescent all week.
  • The Sun currently has 6 active regions and the sunspot number is 110.
  • 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 12th June

  • Astronomical twilight does not end until July 21st.
  • Venus (mag -4.3) passes by M44, the Beehive Cluster, through the early part of this week. Look for the pair above the western horizon an hour or so after sunset.
  • As we approach the Summer Solstice, we enter noctilucent cloud season. Keep an eye out for these magnificent high altitude ‘night shining’ clouds above the northern horizon just after sunset and just before sunrise.
  • If you have a good low southern horizon, try this week’s observing challenge: find Antares, the red supergiant in Scorpio and then hunt down three globular clusters about 8° to the east, M19 (+6.8) 29 kly, NGC 6293 (+8.2) 31 kly, and the most distant of the three, NGC 6284 (+8.8) at about 50 thousand light years from Earth!
  • The Moon is New on Sunday.
  • The Sun currently has 7 active regions and the sunspot number is 116.
  • 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 5th June

  • Astronomical twilight does not end until July 21st.
  • Venus (mag -4.3) continues to dominate our evening sky. Look about 27° above the western horizon at sunset, around 21:15 BST. The two bright stars to its west are Castor and Pollux.
  • Ophiuchus provides a rich observing ground this week, with three Messier Globular Clusters to find. Start with M12 at mag +6.7, then on to M10 (+6.6), both are about 14,000 light years away. Finally a little further east to M14, fainter at mag +7.6 as it is twice as far away at 30,000 light years.
  • The Moon is Last Quarter on Saturday.
  • The Sun currently has 7 active regions and the sunspot number is 112.
  • 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).

 

in What's Up