Martin Lunn from Earby Astronomical Society, tells us what can be seen in the August skies.
AUGUST can be a spectacular month so far as the night sky is concerned. It marks one of the main meteor showers of the year, the Perseids. Although astronomers call them meteors many people refer to these objects flying across the night sky as shooting stars.
The Plough lies north west with the ‘W’ of Cassiopeia at the same height in the north east. The four stars that make the square of Pegasus are becoming more noticeable in the north east and the summer triangle of stars Altair, Deneb and Vega are still very dominant in the summer sky. Arcturus is dropping to the west while Antares is now past its best.
The southern part of the sky is still taken up by the formless Hercules, Ophiuchus and Serpens. Yet more dull constellations are appearing low in the south east; these are Capricornus (the Sea Goat) and Aquarius (the Water Bearer), and although both lie in the zodiac there is nothing else to recommend them.
The stars form patterns that are called constellations and the stories come from Greek legends and myths, while rather confusingly most of the star names we use are of Arabic origin. With the summer triangle stars being overhead it is worthwhile looking at the myths that relate to them.
Aquila, main star Altair
This constellation has Mesopotamian origins, being represented as an eagle in a stone relief dating back to at least 1200 BCE. For the Greeks the eagle, like all creatures from the air, came under the dominion of the supreme god, Zeus, or in Roman myths, Jupiter.
The eagle was the king of the birds, a privileged royal servant and a fighter charged in particular with retrieving the thunderbolts hurled by the great sky god.
Cygnus, main star Deneb
Several Greek myths tell of young men being turned into swans. However the best known and most relevant tale is that of Leda, wife of king Tyndareus. Leda lay both with her husband and with Zeus (Roman Jupiter) who had taken the guise of a swan. As a result of these unions she produced two eggs; from one she bore Helen of Troy, from the other came the twins Castor and Pollux.
Lyra, main star Vega
For the Greeks Lyra was the instrument invented by Hermes and given by Apollo to his son Orpheus. Orpheus journeyed to the underworld to seek his bride Eurydice who had been killed by a viper. Hades, king of the underworld, (Pluto in Roman myth) was touched by his music and permitted Orpheus to take Eurydice back provided that he did not turn to look at her until they emerged from hell. However, at the very last moment Orpheus glanced back, and Eurydice’s soul slipped away for ever.
What’s up in the Solar System?
The Planets in August
Mars and Saturn are still visible low in the south, Mars of course is the red looking ‘star’ while to the left is the fainter yellow looking ‘star’ Saturn and this will be the last month when it will be easy to see them. The other planets Jupiter, Mercury and Venus are very close to the Sun and cannot be seen.
The most anticipated meteor shower of the year, the Perseids will peak on the night on August 12/13 when around 80 meteors per hour can be seen, although many meteors will be seen a day either side.
Many people know meteors as shooting stars; however meteors have nothing at all to do with stars. They are tiny grains of dust that burn up when they enter the Earth’s atmosphere. The will be travelling anywhere from 20 to 50 miles per second and as they heat up and are destroyed we see the result of their destruction in the form of a brief streak of light across the sky.
Although a few sporadic meteors can be seen on any night of the year there are periods when many can be seen, referred to as meteor showers. These meteors are connected with comets. Comets are essentially very large dirty snowballs travelling around the Sun. The comets leave a trail of dust behind them and if the Earth happens to pass through one of these dust trails we see a meteor shower. There are several major meteor showers during the course of the year.
The Perseids are connected with comet Swift-Tuttle which was discovered by Lewis swift and Horrace Tuttle in 1862. The comet takes 133 years to obit the Sun. However the meteor shower has a very long history. They are called Perseids because if you track their paths across the sky they will all appear to come from the constellation of Perseus. It should be possible to see the Perseids after about 11pm, at first from the north east but as the night goes on all over the sky.
An old name for the Perseid meteors shower is the Tears of St Lawrence, in 258 in Rome a Christian named Laurentius, offered the Roman emperor Valertian all the wealth of the empire. Valerian believed that he meant gold and treasure but Laurentius meant the people of the empire. Valerian was very annoyed when he did not get the treasure he was expecting and had Laurentius killed in a most horrible way by having him roasted alive.
This was on August the 9th 258, and the following evening the Perseids came through on schedule and people thought these meteors were tears from heaven, hence the name ‘The Tears of St Lawrence’. The story then goes forward to 1537 when the French explorer Jacques Cartier was exploring the land we now call Canada. In August 1537 while camped besides a large river he saw the Perseid meteor shower, he knew the story of St Lawrence and being the first European there, he named the river after him.
Phases of the Moon for August
New Moon on August 2, First Quarter August 10, Full Moon August 18, Last Quarter August 25
This month’s full moon is called the ‘Sturgeon Moon’. This is the month when Sturgeon would have been caught in the rivers in Britain. They were considered to be royal fish and the first caught had to be given to either the King or the King’s representative.
The next meeting of the Earby Astronomical society will be on Friday, September 30 at All Saints’ Church, Earby from 7.30pm - 9.00pm. The talk will be entitled ‘The Telescope’ and will be presented by Simon Emmott, Earby Astronomical Society.