June 2020 What’s Up!

Week of 29th June

  • Astronomical twilight does not end until 21st July
  • The Earth reaches aphelion on Saturday, the furthest point from the Sun in its annual orbit. It will be at a distance of 1.02 AU. Summer in the Northern hemisphere has nothing to do with the Earth – Sun distance, it is due to the tilt of the Earth’s axis being towards the Sun at this time of year
  • Venus is now a morning object, rising at around 03:30 BST and shining at about mag -4 in the East
  • The Moon is waxing and will be Full on Sunday
  • The Sun has one active region, AR 2766, in the southern hemisphere approaching the off going limb. This is the tenth Solar Cycle 25 sunspot this year, which indicates that the new cycle is gaining strength
  • There are no ISS evening passes visible this week

Week of 22nd June

  • Astronomical twilight does not end until 21st July
  • Jupiter and Saturn are now late evening risers. On Thursday there is a shadow transit of Jupiter’s largest moon, Ganymede. The transit commences at 23:35 BST and continues until 02:50 BST. Look about 8° above the southeastern horizon with binoculars to find Jupiter and observe this event
  • The Moon is waxing and will be First Quarter on Sunday
  • The Sun is quiet again and has no active regions
  • There are no ISS evening passes visible this week

Week of 15th June

  • Astronomical twilight does not end until 21st July
  • A lunar occultation of Venus occurs on Friday morning. Venus will be hidden from view at around 08:37 BST as the Moon passes between it and the Earth. It will re-emerge just over an hour later at about 09:42 BST. As this all happens in daylight with a thin waning crescent Moon, it will be quite tricky to spot the reappearance of Venus, but the start of the occultation should be easier to observe
  • The Summer Solstice is on Saturday. At 22:27 BST the Sun will be at its highest declination of around +23.5°, making 20th June the longest day this year in the Northern Hemisphere. This marks the astronomical start of summer. This day also sees the Sun setting at its most northerly point on the horizon, about 41° north of due West. The Sun used to be in the constellation of Cancer on the Summer Solstice, creating the Tropic of Cancer, the most northerly line of latitude on Earth which sees the Sun directly overhead. However, nowadays, due to precession (the wobble of the Earth on its axis over a 26,000 year period) the Sun is actually in Taurus
  • There is an annular solar eclipse on Sunday morning between 04:47 and 10:34 BST, but it will not be visible from the UK. Only observers in Africa and Asia will be direct witness to this spectacular heavenly event
  • The Moon is waning and will be New on Sunday
  • The Sun has one active region, AR2765, at a high southerly latitude
  • There are no ISS evening passes visible this week

Week of 8th June

  • Astronomical twilight does not end until 21st July
  • Keep an eye out for noctilucent clouds towards the northern horizon in the hour after sunset and before sunrise
  • Jupiter, Saturn and Mars are currently rising at around midnight to 1 am. They will become evening objects in about a month
  • The Moon is waning and will be Last Quarter on Saturday
  • The Sun has one active region, AR2765, at a high southerly latitude
  • There are no ISS evening passes visible this week

Week of 1st June

  • Astronomical twilight does not end until 21st July
  • Mercury reaches greatest eastern elongation on Thursday. Look to the northwest in the hour after sunset to spot Mercury at around 10° altitude
  • Reports suggest that Comet C/2020 F8 (SWAN) has dimmed significantly and is possibly disintegrating. Another comet that has failed to live up to the stories
  • Noctilucent cloud season has started. Look to the North in the hour after sunset to spot these opalescent clouds. They reside in the mesosphere some 80 km above the ground and are formed by water vapour crystallising around particles in the high atmosphere. They reflect the sunlight still able to reach those altitudes as the Sun has not sunk far below the horizon
  • The Moon is waxing and will be Full on Friday
  • The Sun has no active regions, with the current spotless stretch at 29 days
  • The ISS makes just one evening pass this week:
    Monday: 22:12, WSW to SSW, max 13°
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