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Welcome to this month's edition of Eyes on the Night Sky. It feels like no time has passed since the winter constellations graced our skies yet it is nearly already halfway through the year. As the Sun doesn't set lower than 20 degrees below the horizon this month, true darkness only lasts a short time and then ends, with all-night twilight occurring in the north of the UK at the beginning of the month, and towards the end of the month for the south.

For the next couple of months, the skies will become too bright to spot faint nebulae and star clusters but there are other night sky objects to explore, such as planets, double stars and the brighter star clusters, not to forget the stunning craters and features that can be studied on the Moon when it is in phase.

Noctilucent Cloud Season Begins

The month of May heralds the start of noctilucent cloud season. The activity of spotting these clouds has grown in popularity over the years at it requires no equipment to see them and is a pleasant way to spend a night sitting under a beautiful, deep blue summer sky.

©Sam Price

The best time of night to see them is when the brightest stars appear but a show can be elusive and difficult to predict. They can also appear a couple of hours before sunrise. There are some forecasts that can be accessed on websites such as Spaceweather.com. Noctilucent clouds are thought to be composed of ice crystals in the mesosphere, which is the outer layer of the Earth's atmosphere.


Partial Lunar Eclipse (UK)


The Full Moon occurs on 16th May and the New Moon on 30th May. If you are prepared to get up very early, there will be a partial lunar eclipse, starting at around 2.30am from Mid Wales, as the Moon enters the Earth’s shadow – or otherwise known as penumbra. An hour later, you will notice a much darker shadow passing across the top left of the Moon which is the umbra, which is the Earth’s darkest part of the shadow just glancing off the face of the Moon. In other areas of the world such as South and North America, and part of Europe, a total eclipse will occur. You might see the Moon at near totality, turning red as it sets.


The Planets

The planets will make morning appearances throughout the month of May. If you are prepared to get up early, you will spot bright Venus on the horizon, alongside Jupiter and Mars; they can be seen from around 2am until Sunrise, with Saturn rising first, followed by Jupiter, Mars and Venus. Keep looking up and at around 4.49am, you will see the International Space Station making a bright pass across the eastern sky.

Mercury is very well-placed during the early evenings in May. Try to spot it with binoculars first as it sets into the west/northwest horizon from 9pm onwards. Because of the dangers of direct sunlight on optical equipment, it is strongly advised to look for Mercury after the sun has set. A bonus binocular sight to behold is the conjunction of the two day-old Moon alongside Mercury, flanked by the Pleiades star cluster on 2nd May at around 10pm.

On 25th May at 3.50am, there will be a lovely conjunction of Venus and Jupiter sitting above the waning crescent Moon.

A Feast of Globular Clusters


If you have a telescope of eight inches of aperture or larger, take time during May to discover nine globular clusters in the south-eastern sky in and around the constellation of Ophiuchus.

Each globular cluster is a densely-packed ball of gravity-bound stars and they are thought to be the oldest objects in the night sky, therefore containing extremely old stars. On average, each globular cluster contains more than 100,000 stars and they are situated on the outer edges of the Milky Way Galaxy. Some of the brighter globulars may be seen with a smaller telescope if you can access a dark, rural sky.

Co-ordinates of the Globular Clusters

M12: RA 6h 47m 15.51s | Dec –01° 56′ 57.8″
M10:  RA 16h 57.10m | Dec -4° 06´ 04.1″
M14: RA 17h 37m 37.44s | Dec −3° 14′ 48.02″
NGC 6356:  RA 17h 23m 36.35s | Dec −17°48′48.06″
M9: RA 17h 19m 46.34s | Dec −18° 31′ 00.03″
NGC 6235: RA 16h 53m 26.80s | Dec −22°10′ 41.1″
NGC 6284: RA 17h 04m 30.20s | Dec −24°45′ 53.0″
M19: RA 17h 02.6m 39.17s | Dec -26° 16’ 06.3”
M62: RA 17h 01m 14.13s | Dec -30° 06´ 46.1”