EYES ON THE NIGHT SKY - MAY 2019
Welcome to our May edition of Eyes on the Night Sky. Even though the night sky is becoming brighter as we move towards the summer season there are still wonders to be seen with the unaided eyes, binoculars and telescopes. Half of the UK can still enjoy a couple of weeks at the beginning of this month to make the most of true darkness before the sun sets at around 18° below the horizon – creating a perpetual twilight all night, until ‘Astro Darkness’ returns in late July/early August.
An object that needs dark skies is a globular Cluster in Ophiuchus: Messier 10. Situated in the constellation Ophiuchus, it lies 14,300 light years away from Earth and contains 100,000 stars, about the same size as the mighty Hercules Globular Cluster but has under a half of its solar mass (200,000 solar masses)
Charles Messier discovered this object in 1764 and added it to his catalogue (link: ) , describing it as a “nebula, without stars, in the belt of Ophiuchus; near the 30th star of that constellation, of sixth magnitude, according to Flamsteed. This nebula is beautiful and round; one can only see it with difficulty in an ordinary telescope of 3-feet [Focal Length].”
It is known to be one of the youngest globular clusters due to it being poor in metal and has only 3.5% of the heavy elements that is found in our own Sun!
A 3 inch telescope will reveal a bright central core and an 8 inch will start to resolve stars at higher magnification. For a challenge, try to find it with binoculars in a dark sky; it should resolve as a slight, fuzzy patch. A bonus object to find is M12, an ancient globular cluster thought to be nearly as old as the Universe itself!
See if you can find this asterism that resembles a diamond ring. Binoculars and small telescopes are required for this object. The North Star, or Polaris, is the brightest star in this asterism and looks like a glittering diamond. Look for a ring shaped asterism of around eight less bright stars. If you want to know what it looks like, click this spoiler. Polaris is a circumpolar star, meaning that it never sets – and in addition, lies in a direct line with the Earth’s rotational axis and the North Celestial Pole, making it an excellent reference point for aligning certain telescope mounts that move along the Earth’s rotational axis.
May’s meteor shower, Eta Aquarids, peaks in the early hours of the 5th. The Earth is passing though streams of debris left by Halley’s Comet from 24th April to 20th May. This year is predicted to be a good one for this meteor shower, as the peak occurs during the New Moon. The ideal conditions to watch a meteor shower is in an area away from man-made light pollution and when the moon is not present in the sky. It is expected that the maximum number of meteors visible would be around 40 per hour. Due to the low positioning of the Eta Aquarids, access to a good, southern horizon is ideal.
Even though the skies are brightening to a permanent twilight over the summer months, the ethereal Noctilucent clouds put on a wonderful show from the middle of May to early August. Look in the northern skies around 90 minutes to a couple of hours after sunset and before sunrise; you may see these gossamer, high altitude ice-formed clouds which are in the upper Earth’s atmosphere (mesosphere) and lit by the sun’s rays. The cause of these clouds is still being debated, but recent studies have explored Space Shuttle exhaust emissions, dust particles from micro meteors or volcanoes and even a recent increase of methane emissions reaching the upper atmosphere; the molecules then producing water vapour contributing to the cloud displays. All you need to observe these are your dark-adapted eyes and warm clothing.
Watch this video by NASA to find out more:
For lunar enthusiasts, the New Moon falls on 4th May and the Full Moon on 19th May.