By Jenny Winder
What to look out for in the June night sky
All eyes will be on the transit of Venus at the start of the month, but there is plenty more for stargazers to look forward to in June.
The Moon will be full on June 4th and there will be a partial lunar eclipse visible across most of Australia, the Pacific Ocean, North and South America. It begins at 08:48 UTC and ends at 13:18 UTC. Greatest eclipse will be at 11:03 UTC when 37% of the Moon around crater Tycho will be dark and take on a red colour due to refraction of sunlight through Earth’s atmosphere. New Moon will be on June 19th and Summer Solstice occurs for the Northern hemisphere at 23:09 UTC on June 20th. From then on the nights will get longer.
The big show happens between June 5th and 6th when Venus makes the last transit across the face of the Sun this century. Transits happen in pairs, after 121.5 years a pair of transits occur 8 years apart, then 105.5 years pass before another pair of transits with an 8 year gap between and the pattern repeats. So the next transit after this wont be until 2117. There have only been 6 transits since the invention of the telescope and only 4 since the invention of photography. Transits have been used in the past to calculate the distance to the Sun and the size of our Solar System. This transit will be visible across most of the globe, apart from much of West Africa, the Atlantic & South America. The UK will only see the tail end of the transit after Sunrise at around 04:47 BST. Times for the transit are: First contact at 22:03 UTC June 5th. Greatest transit at 01:29 UTC June 6th and last contact at 04:54 UTC June 6th. You will need to find a good location with a clear view of the Eastern horizon. Remember you must never look directly at the Sun, be sure to use proper solar filters or eclipse glasses to view this once in a lifetime event.
Three related constellations grace the night sky to the South this month. Lying beneath the keystone of Hercules, Ophiuchus, (the Serpent Bearer) bisects the Serpens constellation in two holding the serpent by its head (Serpens Caput) and its tail (Serpens Cauda) With prolonged astronomical twilight at this time year we are firmly in globular cluster season and Ophiuchus boasts no fewer than 33 of them. M10 and M12 were both discovered in 1764 by Charles Messier. M10 is about 83 light years across and 14,3000 light years away while M12 is 73 light years in diameter and 15,700 light years from Earth. M5 in Serpens Caput is 655 light years across, making it one of the largest globular clusters known. It is also one of the oldest associated with our galaxy at 13 billion years old. M16 in Serpens Cauda is the amazing Eagle Nebula an active star forming region that contains the open star cluster NGC 6611 and also the ‘Pillars of Creation’ made famous by the 1995 image taken by the Hubble Telescope.