As we head into June looking forward to some long and hot summer days, astronomers prepare for the more challenging nights of observation.
June 21 marks the summer solstice in the northern hemisphere. It marks the point in the Earth’s orbit around the Sun where the north pole is at its maximum tilt towards the Sun.
As a result, we see the Sun reach its highest position in the sky and have the longest hours of daylight.
For a good few weeks either side of this date (throughout all of June), the days are generally long and this means that astronomers have the shortest nights to observe the skies.
What’s more is that during June the Sun never sets far enough below the horizon for it to ever get truly dark at night – we remain in twilight.
Although stargazing can prove most difficult during June, there is a spectacle that only occurs in the summer – the appearance of noctilucent clouds.
These clouds appear higher up in the atmosphere than any others and contain ice crystals which reflect sunlight and shine with an electric-blue tint.
Looking in the direction of north, these clouds are only seen at latitudes of about 50-65 north (and accordingly in the south) during the few weeks either side of the solstice.
Wait until the skies get dark (as the brightest stars begin to appear) – they’ll be illuminated by the Sun even though it will be hidden below the horizon.
Both Jupiter and Saturn will be high enough above the southern horizon to be seen together around midnight towards the end of month.
Spot Jupiter to the west of the full moon on the 17th and by the 19th the moon will be beside Saturn – further to the east.
Use a telescope to take a closer look when there’s less moonlight to interfere!
Just after midnight, when the skies are most ideal for stargazing, look for the constellation of Hercules placed high in the southern sky throughout June.
An approximately square-shaped pattern of four stars known as the keystone asterism lies at the centre of this constellation and between the two stars on the right lies M13 – debatably the finest globular cluster visible in the UK.
This collection of several hundred thousand stars is 22,000 light years away and is easily visible through a pair of binoculars on a clear night