The August Night Sky

August, it’s one of our favourite months of the year. Whether you’ve been on your summer holidays or not, August is a month to relax, and have fun with family and friends. The month August was named after the infamous Roman Emperor, Augustus Caesar. He was the grandnephew of the Emperor Julius Caesar (who the month of July was named after) and is best known for his defeat of Marc Anthony and Cleopatra. A final interesting fact about the month of August is that when it was named, it was decided that the month should also have 31 days like July. In order to accommodate this, an extra day was taken from February, which originally had 29 days, and 30 on a leap year, and it was added onto the end of August.

 

Where to find the Perseid Radiant (Image credit: NASA)

Where to find the Perseid Radiant (Image credit: NASA)

 

The first event we have in August that all budding astronomers can look forward to is the Perseids Meteor Shower. This meteor shower starts around 17 July and continues on until 24 August. The shower hits its peak on 12th and 13th of this month, so this is the best time to camp out with your friends and family to see the show. This particular meteor shower is heralded as one of the best showers of the year; however you can only see it in the Northern Hemisphere, so if you’re on holidays in the Southern Hemisphere you will not be able to see it. The Perseids Shower is produced by  Comet Swift-Tuttle. The comet was first observed by Lewis Swift on 16th July 1862 and then by Horace Parnell Tuttle on 19th July 1862. The Perseids can produce up to 60 meteors per hour and a large number of these are quite bright. There will be a crescent moon in the sky but it will be no match for these bright meteors. The best place to view this spectacular show is after midnight in a dark location, away from any light pollution. The meteors will radiate from the constellation of Perseus, however they can appear anywhere in the night sky.

On 14 August there will be a New Moon in the sky, so this will be a time to marvel at all of the stars without the hindrance of moonlight. What do we suggest you see? With the Universe right in front of us there is so much to see, so here are a few of the highlights.

The Summer Triangle is still in the sky, and we talked about the three main stars of this pretend pattern in our July Night Sky article. These three main stars, Altair, Deneb and Vega belong to different constellations, so in August why not take a closer look at some of the other stars in these constellations.

Starting in the constellation of Aquila we have the star known as Tarazed, or Gamma Aquilae. It is an orange, bright giant star with an apparent magnitude of roughly 2.72. It’s relatively young with an age of about 100 million years. It is the 118th brightest star in the night sky and we recommend you look out for this star as it is easy to spot with the naked eye. It lies just north of the star Altair.

Tarazed and Altair are neighbours in our sky but are hundreds of light years apart in the Milky Way. (Image credit: Colin Johnston/Armagh Planetarium/Stellarium)

Tarazed and Altair are neighbours in our sky but are hundreds of light years apart in the Milky Way. (Image credit: Colin Johnston/Armagh Planetarium/Stellarium)

Moving upward to the constellation of Cygnus, we’re going to look at a very special star. It is called Albireo, or Beta Cygni. For all of you amateur astronomers out there this star is a gem in the sky. With the naked eye it looks to be a single star but if you look through a telescope you will see that Albireo is actually a double star. These two stars are what they call a binary star system. A binary star system is defined as being two stars orbiting around a common centre of mass. The most wonderful thing about Albireo is that the two stars have a great contrast in colour. The brighter of the two appears to be gold, with the dimmer one appearing to be blue.

 

Where to look for Albereo. Deneb, Vega and Altair mark the vertices of the famous Summer Triangle. (Image credit: Colin Johnston/Armagh Planetarium/ Stellarium)

Where to look for Albereo (circled). Deneb, Vega and Altair mark the vertices of the famous Summer Triangle. (Image credit: Colin Johnston/Armagh Planetarium/ Stellarium)

 

If you can’t get enough of double stars then in the constellation of Lyra we have some more amazing examples to see. Beta Lyrae, also known as Sheliak, is a double star found in this constellation. Beta Lyrae is what is known as an eclipsing binary, a variable star whose changes in brightness are caused by eclipses of two stars in a tight orbit binary system. Beta Lyrae is approximately 960 light-years away, so you will need a telescope to see it.

The constellation of Lyra also holds another impressive celestial object that any aspiring astronomer should try and catch a glimpse of. If you thought double stars were impressive, then you’ll be itching to see The Double Double, also known as Epsilon Lyrae. It is a lot closer to us than Beta Lyrae, lying only 162 light-years away. An ordinary pair of binoculars will make you believe that you’re looking at an ordinary double star, but with a telescope you will be able to see that each component star has a double, making it the Double Double. Trust us when we say, it’s truly a sight to behold.

M57, the Ring Nebula (the little oval almost mid way between Gamma and Beta Lyrae) looks tiny, but it appears blarger that giant Jupiter in your eyepiece. (Image Credit: NASA, ESA, Digitized Sky Survey 2)

M57, the Ring Nebula (the little oval almost mid way between Gamma and Beta Lyrae) looks tiny, but it appears larger that giant Jupiter in your eyepiece. (Image Credit: NASA, ESA, Digitized Sky Survey 2)

If you want to see something a little different, why not try and look out for Messier 57 (M57), or “The Ring” Nebula. It is located between the bottom two stars in the constellations of Lyra. This nebula was first discovered by the French Astronomer Antoine Darquier de Pellepoix in 1779.

If you would like to see some other constellations this August, why not try and spot the circumpolar constellations. These constellations are brilliant for young and budding astronomers to learn, as they are always in the sky and you can see them on a clear night. The circumpolar constellations are the patterns that endlessly rotate around the Pole Star, Polaris (North Star). The most famous of these is Ursa Major, the Great Bear. In this constellation you can find the Plough, also known as the Big Dipper, and it is undoubtedly one of the most famous patterns in the night sky.We’re all very familiar with the Plough and Ursa Major so let’s look at the other circumpolar constellations.

Camelopardalis is one of the groups of animals that circle around the Pole Star. Its name comes from the Latin derivation of the Greek word for Giraffe. It is the 18th largest constellation in the sky. An interesting fact about this constellation is that the space probe Voyager 1 (launched 5 September 1977) is moving in the direction of Camelopardalis however it will not near any of the stars in the constellation for many thousands of years, by which time the power source of the probe will have been long dead.

Draco, the mighty dragon in the sky (Image credit: Heather Taylor/Armagh Planetarium/Stellarium)

Draco, the mighty dragon in the sky (Image credit: Heather Taylor/Armagh Planetarium/Stellarium)

Draco the Dragon is the eighth largest constellation in the sky and was first recorded by Ptolemy in the 2nd Century. There are several myths surrounding this constellation, but the most prominent links it to another constellation. In Greek mythology Draco is said to represent the dragon Ladon, who was placed around a tree bearing golden apples by the goddess Hera. One of the twelve trials of Hercules was to steal some of these golden apples. Hercules killed Ladon with poisoned arrows and took the apples. Hera was saddened by the death of the dragon and so placed him into the sky.

Cassiopeia the Queen and Cepheus the King are two of the circumpolar constellations that are connected by their myths. Cassiopeia was the vain, boastful Queen of Ethiopia. She proclaimed that she was even more beautiful than the Nereids (the Sea Nymphs). Enraged by this the Nereids went to Poseidon the god of the sea, who was married to one of the Nymphs. They asked him to punish Cassiopeia for her boastful ways and the god obliged. He sent the sea monster Cetus to ravage the coast of King Cepheus’ Kingdom. After consulting an oracle on how he could save his kingdom from the sea monster, Cepheus was told he must sacrifice his daughter Andromeda to the monster. The King and Queen reluctantly obliged and had their daughter tied to a rock. Andromeda was saved by Perseus, who later went on to marry her. At the wedding a former suitor for Andromeda proclaimed that he was the only one who could marry the princess and fought Perseus. Perseus defeated the suitor by using the head of Medusa the gorgon, who he’d slain previously. The suitor was defeated, however Cepheus and Cassiopeia were also killed by being turned to stone as they did not look away from the head of the gorgon. Poseidon was then able to condemn Cassiopeia and Cepheus to an eternity in the sky, endlessly rotating around in the heavens, spending half of the year upside down. Finally we have Ursa Minor the Little Bear, the smaller counter part of Ursa Major the Great Bear. Ursa Minor boasts the most famous star in the sky. Polaris, or the North Star, makes the tip of the tail of the little bear.

To end this month of stargazing, we end on a full moon on 29th August. The night sky will be flooded by the brilliant light of the moon, so it will be a little harder to find some of the stars and objects in the sky. This moon is known as the Full Sturgeon Moon. It got this name because it is said that sturgeons, a large fish common to the Great Lakes of North America, are easily caught during this month. The Moon can also appear to have a reddish glow to it, so in other cultures it is also known as the Red Moon.

(Article by Heather Taylor, Education Support Officer)