In May 2021, the bright planet Venus is slowly rising in the evening skies and may be glimpsed in the dusk sky in the western sky. The elusive planet Mercury may be spotted close to the brighter Venus on May 29. Mars is still just about visible in the western sky after sunset but is fading fast as we on our orbit move away from it.
While the May night sky lacks the more prolific and brighter stars of winter, it has some bright stars. At about 10.00 pm looking south, there are three bright stars, easily spotted, Regulus in the constellation Leo, the lion, is more or less due south, to the left of it is the Spica in the constellation of Virgo the Virgin, further left but up is the star Arcturus in the constellation of Bootes, the herdsman. Regulus is the brightest star in Leo. The name means "royal star", which acknowledges the role of the lion as the King of the beasts. Regulus (and Spica) almost sit on the imaginary line, the ecliptic; this is the name given to the path upon which the Sun, Moon and Planets can be seen. On rare occasions, Regulus and Spica be occulted by the Moon or even rare occasions by a planet.
To find all three is relatively easy. If you find the well-known asterism of the Plough, which is almost overhead at this time of year, follow the curve of the handle down, and you will come to a bright star. This is the star Arcturus. Then follow this same line down toward the horizon, you will come to Spica in Virgo. Then to the right of Spica, more or less due south, you will come across the star Regulus. This line or arc in the sky allows astronomers to tell potential stargazers to "...follow the Arc to Arcturus and then speed onto Spica" It works; just try it for yourself.
Leo is quite distinctive and is often seen as one of the few constellations that look a bit like it what is meant to represent. More easily recognised in Leo, above Regulus is the sickle shape (or reversed question mark), which is relatively easy to spot. To the east (or left) of Leo is another zodiacal constellation, Virgo, which also has the bright star Spica. Virgo represents the Virgin, and her brightest star Spica, is usually depicted as having a sheaf of wheat in her hand, hence the name. Virgo tends to be seen as a big letter "Y" with Spica at the bottom. This enables us to use the "Y" shape to describe a feature in Virgo that can be seen on a dark, clear night. The bowl of Virgo is an area that is rich in galaxies and other faint objects. When we look at this area of the sky, we look beyond our Milky way at features that are a huge distance away from us. Travelling at the speed of light, 186,000 miles per second, the Galaxies in this area of the sky are so far away that if we could travel at the speed of light, it would take us 13 billion years to reach them.
Above Virgo is the even more spectacular Coma cluster, so named because it is within the constellation of Coma Berenices. Like the Virgo cluster, the Coma cluster is rich in Galaxies and is also a huge distance away.
The constellation mythology is a great tale with a hint of truth from an observational perspective. According to the legend, King Ptolemy had waged a long war on the Assyrians, as they had killed his sister. When he returned successfully from the war, his wife Berenice, as a tribute, had her beautiful hair ceremoniously clipped and given to Aphrodite. It was laid out on the altar. The following day the hair was discovered to be missing. The King was furious and hinted that the priests might be sacrificed if the queen's hair couldn't be found. It was the astronomer Conon of Samos who came to their rescue. He advised that Aphrodite had accepted the gift of Berenice's hair, which now is in the heavens next to Leo, there for all eternity to celebrate the Kings triumph. Well, look for yourself, on a dark moonless night, find the bright star Spica and look above it, for the "Y" shape of the bowl of Virgo. Just above the bowl, you may see a glimpse of a faint shimmering feature, which looks a little like hair. You are actually looking at galaxies that are 13 million light-years away.
The final object we will look at in our May night sky is the constellation of Bootes, the herdsman, and the bright star Arcturus. To find it, locate for yourself the stars of the Plough, which at this time of year is almost directly overhead. Follow the curve of the handle downwards towards the left or east. You will come to another bright star, Arcturus, which has a distinctive orangey- white colour. Arcturus is at the bottom of a kite-shaped constellation that is relatively easy to spot in a dark sky. Arcturus was probably one of the best-known stars for a short while back in 1933.
In 1933 Chicago wanted something extraordinary and innovative to mark the opening of its "Century of Progress Expo." It was looking for a way to indicate just how far the city had come since its establishment 100 years earlier. The organisers wanted to pay tribute to the World's Columbian Expo of 1893 held in Chicago held to commemorate the arrival of Columbus 400 years in 1492. A unique idea was born to light up the 1933 Expo site using a light beam that first left a star in 1893. Astronomers at the time estimated that Arcturus was located 40 light-years from Earth. The light emitted from Arcturus during the World's Columbian Exposition in 1893 would reach the Earth in 1933, in time for the opening of the "Century of Progress" Expo.
So, at 9:15 pm on May 27 1933, four telescopes located in different observatories in the region captured the light from Arcturus and sent it to the Expo site and lit up the floodlights before a crowd of 30,000. We now believe that Arcturus is a little nearer at 37 light-years away. In 1933, Arcturus was one of the most famous stars in the cosmos. Even today, this feat is seen as a "shining" example of the technological progress of the time.
May 3 - Mercury and Pleaides above Venus, in the evening sky
May 4 - Jupiter and Saturn close to Moon, in the morning sky
May 5/6 - The Eta Aquarids Meteor Shower. This shower runs from 19/4 to 28/5. The shower originates from comet Halley. Peaking on the night of May 5-6. Moonlight will not be an issue in 2021. Look for meteors in the eastern sky after midnight.
May 11 - New Moon (20:01 BST) This is the best time of the month to observe faint objects as there is no moonlight
May 14 - The distinctly red but rapidly fading Mars is just above Moon
May 17 - Mercury is at its greatest distance from the Sun in the evening sky. At an elongation of 22 degrees from the Sun
May 26 - Full, and a Supermoon (the closest supermoon of the year, the Moon will be 357,314 km away). There is also a total Lunar eclipse. The eclipse is not visible from the IOM but visible around the Pacific coast.
May 29 - Venus and Mercury are close in the evening sky, just 0024' apart
Howard Parkin FRAS