So, it’s been a weird spring so far this year, with most people working from home and stuck in their houses. But we’ve been getting some good weather over the last few weeks, allowing us to get out for our daily exercise, or even just into the garden. Well, now might be a good time to take advantage of the good weather and lack of clouds for a bit of stargazing! Grab a seat in your garden, or simply look out the window for a view of our spring sky this year. And a silver lining to our predicament; less light pollution, so the night sky might be even clearer than normal where you are!
The first event that will take place this month is the Eta Aquarids. This is a meteor shower that will emanate from the constellation of Aquarius, and is caused by the most famous comet, Halley. This is quite an unusual meteor shower, as it lasts a long time (19th Apr – 28th May) and doesn’t have a sharp peak as many other showers do. Instead, this shower will peak for about a week, giving us more opportunity to see some great meteors passing overhead. Now, it is more easily seen in the Southern Hemisphere, but have a look out in the mornings of the days surrounding the fifth of May for the shower’s peak, which might allow us here in the Northern Hemisphere so see up to 30 meteors per hour. Conditions for viewing the meteor shower aren’t perfect, given that the bright, nearly full moon will outshine most meteors at the shower’s peak, but take a look anyway, and you should be able to see a few good meteors this month!
Following closely after the peak of the Eta Aquarids comes the full moon, brightest on the 7th of May. Pesky though it will be to have the moon so bright when the meteor shower is happening, this full moon will be something to look out for: yet another supermoon – the fourth of the year so far, and 2020’s last. This full moon is known as the full flower moon, a lovely spring title; but it also has a few other names depending on where you look. The moon was also known as the mother’s moon, the milk moon, or the corn planting moon, all based on the increasing fertility in nature at this time of year.
On the other side of the coin, the new moon will take place on the 23rd of this month – around then will be the best nights of the month to go stargazing, without the moon’s brightness interfering with the light from the stars.
We also have an exciting event taking place this May – a comet will make its closest approach to Earth. This is the recently discovered Comet Atlas, first spotted in December 2019 by the observatory at Mauna Loa in Hawaii. The comet has been increasing in brightness since February, and is predicted by some to increase in brightness to a maximum of between +1 and –5 – which would make it the second brightest object in the night sky, after the moon (which will be new at this time of the month anyway!). However, comets are notoriously difficult to predict accurately so another prediction is that it will not reach naked eye brightness at all! But it will be visible with a telescope or binoculars in the constellation of Camelopardalis the giraffe, in the North of the sky up until mid-May, and in the constellation of Perseus, so break out the binoculars and watch out to see what actually happens!
Camelopardalis itself is a lesser-known constellation, but it’s a great one for stargazers to look out for all year round as it is visible in the North of the sky at any time of year. It’s pretty dim, with no bright stars (which is why it’s lesser known) but it’s one of the circumpolar constellations, which endlessly circle the north star. Camelopardalis is named after the giraffe, and its brightest star is Beta Camelopardalis, a double star. The primary star of this pair is a yellow supergiant 1000 light years away from Earth. Camelopardalis also has one of the most distant stars visible with the naked eye from Earth, a blue supergiant star over 6000 light years away.
Camelopardalis was created in 1613 by the Dutch astronomer Petrus Plancius and contains the asterism known as Kemble’s cascade, which is a faint but beautiful group of more than 20 stars in a line of a length about five times the width of the moon. It points to the Cassiopeia constellation and ends with a small open cluster of stars, NGC 1502. This object consists of 45 stars, and the whole asterism appears to form a waterfall, with stars ‘flowing’ into the open cluster.
Another deep sky object visible in Camelopardalis is a beautiful planetary Nebula, the Oyster Nebula. A planetary nebula is a star which has puffed off its outer layers late in its life. What we get is a small white dwarf star right at the centre of the nebula, with a large and colourful shell of gases surrounding it.
Because the Camelopardalis constellation was discovered so recently, it does not have any mythology associated with it… no fun story to tell here, then. Sorry!
Look out in the early mornings of this month for Jupiter and Saturn, low in the sky and close together. They will be bright and between the constellations of Capricorn and Aquarius.
Low in the sky in the early mornings of May, another visible constellation is Ophiuchus and Serpens. Ophiucus is the serpent bearer, and is associated with the great healer Asclepius, son of Apollo in Greek mythology. Asclepius was taught the art of healing by the centaur Chiron. In one version of the tale, Asclepius discovered the secret to eternal life after he was given the head of the Gorgon Medusa (represented by the serpent). The blood that flowed out of the veins on one side of the head was poisonous, but the blood from the other side could restore life. In another version, he was able to resurrect a prince after he was thrown from his chariot. Either way, Asclepius discovered the secret to eternal life, and was punished for it. Hades, God of the underworld, was worried that no more human souls would pass on to the underworld due to Asclepius’ discovery. Hades persuaded his brother Zeus to be worried as well, and Zeus killed Asclepius with a lightning bolt. However, Zeus appeared to have some sympathy for the healer, and Asclepius’ image was placed in the sky to honour his good work. This constellation became the serpent bearer.
An alternative mythology is that this constellation represents an ancient Babylonian god Nirah, who had a human torso and head, but serpents for legs.
Ophiuchus has some really stunning stars. Zeta Ophiuchus is a fast rotating star, a large blue main sequence star. This star will expand in the future, becoming a red supergiant and eventually exploding in a supernova. After this it will likely become a pulsar.
One of the stars within the constellation is a red dwarf with an extrasolar planet. The star is much smaller than the sun, allowing the planet to orbit much closer to the star than Earth. The planet is much bigger than Earth but orbits its star in just a day and a half!
Finally, also in Ophiuchus is a very young supernova remnant first observed in 1604. This has been an extremely well-observed object – Johannes Kepler discovered it on October 17th and then watched it for a whole year. A supernova is the explosion at the end of a large star’s life, and this one occurred 20,000 light years from Earth. It became brighter than all the stars and planets in the night sky at its peak brightness, beaten only by the moon. It could even be seen during the day for a few weeks. It is the most recent supernova (that can be seen with the naked eye) in the Milky Way.
The constellation Serpens is technically a different constellation to Ophiuchus, though. It is divided in two by Ophiuchus, and the two parts are called Serpens Caput (Serpent’s Head) and Serpens Cauda (Serpent’s tail).
Serpens contains one of the most famous objects in the night sky, M16, the Eagle Nebula. This is a star-forming nebula, and contains the famous Pillars of Creation. Take a minute to appreciate one of the most magnificent sights in the galaxy.
So with that happy, calming image, I will let you get back to whatever you were doing in isolation. Stay strong, stay safe, and stay home.