Sky Notes for June 2013 with James Abbott #stargazing
The Summer Solstice this year takes place on June 21st just after 6am BST – an hour and a half after sunrise. At local noon on the 21st, the Sun beams down from an altitude of nearly 62 degrees, as high in the sky as is currently possible from our latitude.
The June Full Moon follows on the night of the 22nd/23rd, low down in the Southern sky. With the Moon near perigee (closest to the Earth) it will appear larger than usual, with the added effect of the Moon Illusion due to low altitude.
Saturn remains well placed in the late evening sky, about 12 degrees to the left of the bright star Spica in Virgo. The waxing gibbous Moon will pass about 5 degrees below the ringed planet on the night of the 19th/20th. With the rings now wide open, only a small part of the Southern Hemisphere can be seen, but the Northern Hemisphere is well presented. Leading amateurs have been able to image the Polar “hexagon”. Visually this feature can appear quite dark compared to the rest of the hemisphere.
Venus should be glimpsed after Sunset low in the North West in Gemini, joined for most of the month by Mercury with a separation distance of around 4 degrees until mid-month. On the 11th the pair are below the lead stars in Gemini, Castor and Pollux, and are joined by a thin crescent New Moon, just 9% illuminated. After mid-month, the 2 planets close and on the 20th are just 2 degrees apart. Towards the end of the month Mercury moves back towards the Sun whilst Venus continues to improve and by the 25th is in a line with the 2 lead stars of The Twins. Mercury will be of similar brightness to the Twins, but Venus will be much brighter, attaining mag -3.9 by the end of June.
The lingering twilight of June and their low altitude will make observations of the 2 inner planets tricky and a transparent sky and a clear horizon will be needed for success.
The time around the Solstice is usually the best for observing noctilucent clouds (NLC). These are high atmosphere formations thought to be composed of small ice-coated particles. They form at very high altitudes – around 82 km above sea level – and so are a quite separate phenomenon from normal weather. They are best seen from our latitude after sunset and before sunrise. The period from 10.30 pm to 11 pm BST is a good time to look, towards the North West and in the twilight glow. The clouds take a variety of forms, more often silvery interwoven streaks and waves.
Spaceweather.com is now posting daily satellite images of NLCs from the NASA AIM spacecraft (look down the left-hand side). The Aeronomy of Ice in the Mesosphere (AIM) mission is exploring Polar Mesospheric Clouds (PMCs), also called NLCs, to find out why they form and why they are changing.
James Abbott is an astronomer, NEAS member and CfDS Regional Information Officer.
Posted on 1 June, 2013, in Astronomy News, Observing News, Popular Science, Stargazing and tagged mesospheric, moon, noctilucent clouds, saturn, solstice. Bookmark the permalink. Comments Off on Sky Notes for June 2013 with James Abbott #stargazing.