Welcome to this month’s update to what’s in the night sky for May.
In the Elan Valley International Dark Sky Park, darkness falls at around 11.15pm. On 19th May, astro-darkness ends and all-night summer twilight begins, which means the Milky Way and fainter celestial objects becomes more difficult to see.
An all-sky view of the constellations from 12am in May from in-the-sky.org
Facing south from midnight, you will see the constellations of Virgo, Libra, Boötes and Corvus. Leo and Cancer marches westwards and Gemini begins to set in on the western horizon. The summer constellations of Corona Borealis, Hercules and Lyra are well-placed in the east, with Cygnus, Ophiuchus, Sagitta and Aquila rising on the eastern horizon.
The Full Moon occurs on 12th May and New Moon on 27th May.
The Planets in May
Venus is currently an early morning object, rising at 4.24am at the beginning of the month and 3.25am at the end. You won’t miss it as it appears as a bright star in the east. If you have a telescope to hand, try looking at it before the Sun rises as you will be able to spot this planet in the waxing crescent phase. To see this, you will need a 3-inch telescope at around 120x magnification.
On 1st June, Venus will be at greatest western elongation.
Saturn is a morning object and rises in the east at 4.50am at the beginning of the month and 2.50am at the end.
Jupiter appears low in the western sky and sets at 11.45pm at the beginning of the month and on the 23rd May, can still be seen very low on the north western horizon, setting at 10.30pm. After then, the skies are too bright for it to be seen.
Mars appears high on the south-western horizon at the beginning of the month, setting at around 2.40am on 1st May and 1.30am on 31st May.
Conjunction of the Moon, Venus and Saturn
On 23rd May, for early risers, there will be a conjunction of the Moon, Venus and Saturn all situated low on the eastern horizon. The Moon will appear as a thin waxing crescent and earthshine or ‘ashen glow’ can be seen on its shadowed face.
Spot Lunar X and Y
On 5th May, you can spot the Lunar X! This is a special effect created by the sunlight bouncing off the rims of craters of Blanchinus, Purback and La Caille. This can be seen in the early hours of the morning at 1.14am. Scan the southern third of the Moon’s terminator until you see an ‘X’ pop into view. Move northwards along the terminator to nearly halfway up and you will also see a ‘V’ appear in the eyepiece.
Constellation of the Month
Each month, we will feature a constellation and the mythology behind it.
There are 88 IAU recognised constellations in the night sky and around 36 that are observable in the northern hemisphere. Some of the names of the 88 IAU recognised constellations are several thousands of years old.
With the advent of science and rational thinking, and more of a focus on the observable world, stars are no longer used for the farming calendar, for navigation or conveying social or religious values.
Get outside and see if you can spot these constellations. The best time to see each constellation we feature is around 90 minutes after sunset.
Constellation of the Month – Corvus
Corvus is a small constellation which lies low on the southern horizon between March and June.
This trapezium of stars represents the white-feathered crow or raven which belonged to Apollo according to Greek mythology.
Apollo was suspicious about one of Coronis, one of his lovers, and instructed his pet crow to watch over her and guard her from becoming too wayward.
He obeyed, but one day, Coronis fell in love with Ischys, who was mortal but Corvus failed to prevent this. He reported this to Apollo, who became furious and scorched his feathers black as punishment – creating a legend of the origin of why corvids have black plumage.
The Babylonians also associated this constellation with MUL.UGA.MUSHEN, associated with Adad, the god of rain and storms.
The ‘Star Gate’ Asterism
RA: 12 h, 35 m, 59 s | DEC: -12° 03′ 09″
An asterism is a collection of stars that are formed into a familiar pattern – this is how we learn the constellations of the night sky. Some asterisms are created just for fun and can add a bit of light relief when searching for fainter objects. Some resemble numbers, letters, jewellery, a coat hanger and even a stargate!
Situated between the constellations of Corvus and Virgo, this asterism’s shape is unusually geometric and was recently named after the fictional stargate in the 70s science fiction television program ‘Buck Rogers in the 25th Century’. This isn’t an open star cluster as there are vast distances between the five stars and are not in the same ‘neighbourhood’.
This asterism comprises six stars and are between 285 and 486 light years away.
Credit: Mark Johnston
Use your small telescope and 100x magnification and higher to spot this asterism.
Noctilucent Cloud Season Begins
This month heralds the beginning of Nocilucent Cloud season, commencing around the 23rd May.
Also known as ‘Night Shining Clouds’, or polar mesospheric clouds, these are composed of tiny ice crystals and sit from 47-53 miles high up in our atmosphere.
The sun sets above 16 degrees below the horizon and some of that light shines into the sky all night (astro-twilight). That light will also illuminate these clouds which lie on the northern horizon and shimmer with an ethereal light.
The best time to see these is between 90 to 120 minutes after sunset or 90 to 120 minutes before sunrise.
The cause of these clouds is still being debated, but recent studies have explored the effects of 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. To keep an eye on the forecasts, visit www.spaceweather.com and keep up with user updates.
Credit: Slava Auchynnikau at unsplash
