It has been a while since Star Lore 4, but now we add to the 25 constellations already looked at, along with their navigational uses, and myths associated with them by the Greeks, Babylonians, and some Indigenous peoples.
For those who have not read the other blogs in the series here are some links:
Star Lore 1
Star Lore 2
Star Lore 3
Star Lore 4
In this blog we take a quick look at longitude and latitude and some ways in which navigators have tried to estimate them to use in their journeying before the use of GPS’s, sextants and a watch/chronograph, before taking another 7 constellations to take us up to 32 in total.
Longitude and latitude
Finding your latitude using the Pole star
Once you have determined which direction is North, you can use Polaris to determine how far north you are - your latitude. As shown in the inset to the image, when you face Polaris (i.e. are looking north), the angle between the horizon and Polaris is equivalent to your latitude. For example, from south of the UK Polaris will be about 52 degrees above the horizon, indicating a latitude of 52 degrees north. Polaris will be directly overhead at the North Pole, and on the horizon at the equator.
Seafarers can measure latitude most accurately using tools like a sextant, but latitude can also be estimated using only your hands. Extend your arms and make fists. Measure the distance between the horizon and the North Star by stacking your fists one over the other. Each outstretched fist measures about ten degrees latitude and that means each finger is roughly 2 degrees latitude. If you do this in the UK, it takes about 5 fists to go from the horizon to Polaris.
The Arabs navigating the Mediterranean, Red Sea, Indian Ocean area used to use a simple type of sextant called a kamal to find their latitude and to help navigate to different ports. The kamal was used from around the 9th century and was in use up until the 19th century and was adopted by Indian, Chinese, and European sailors. It was an ingenious, yet simple, device, consisting of a small (2 x 1 inch) rectangle of wood or bone with a hole in the middle in which a length of cordage with regular knots was tied. Traditionally, these knots were tied every finger width. At their home port, the navigator would hold the cord against their mouth with one hand and the rectangular ‘card’ of the kamal outstretched in the other so that the top edge was aligned with Polaris and the bottom edge on the horizon. This way they would know which knot denoted the latitude of their home port. They would know which knot denoted the latitude of their port of destination (or a waypoint) and could therefore sail, north or south as needed until they reached that latitude. They would then sail east or west, using the kamal to keep them on the correct latitude, until they reached the destination (or waypoint). This was called latitude sailing. The narrow width of the ‘card’ meant that it worked best in latitudes in which the angle between Polaris and the horizon is narrow and so this method is less precise in northern Europe because of the greater angle of the Polaris in relation to the horizon.
Calculating longitude
A marine navigator knows that finding their bearing and latitude is only half the battle. To navigate on open waters, seafarers must also know their longitude, or their position east or west of the prime meridian. Unfortunately, longitude is extremely difficult to determine using the stars alone. Some early navigators may have calculated their longitude by tracking the movement of rise and set stars across the sky. By recording the position of a specific rise and set star every night at the same exact time, mariners could get an estimate of how far they had travelled west or east the previous day. Star positions must be recorded every day of a journey, beginning with the known longitude of the location where the voyage began. This method of calculating longitude required careful record-keeping and was still prone to miscalculations. Polynesians relied on the positions of stars to guide them along their voyaging routes. Stars hold their positions steady in the sky throughout the year, although the time of a star's rising or setting changes seasonally. Stars low near the horizon - just risen or about to set - are guiding stars, used for setting the direction of the canoe until they rise too high in the sky to follow easily. Once they've risen higher, another star that rises or sets at the same point on the horizon is used by the navigator in its place. In this way, a whole series of stars are strung together in a path, indicating throughout the night the direction of the island destination. The course being followed and the canoe's latitude determine how many stars are needed in succession, but an average night's voyage could require a path of 10 stars.
Polynesian navigators oriented themselves according to their departure point. Leaving land for a known destination, the navigator lined up two or more landmarks to set off in the right direction. As landmarks faded and night came on, they took new bearings from stars. At any time during the voyage - days or weeks out - a navigator could work their path backwards and identify the direction of the island they had left.
Zenith stars, also used in navigation, are those that appear to pass directly over an island when the canoe is at the same latitude (positions due east or due west of the island). Polynesians could not determine longitude so to make landfall, they aimed far upwind and up current (usually east) at the correct latitude, then sailed downwind using the destination island's zenith star as a guide until they hit land. Examples of zenith stars are Sirius, the brightest star in the sky which is the zenith star for Ra`iatea, and Arcturus, which is the zenith star for Hawaii.
Constellations
Below we have our updated map. In the first 4 blogs we looked at 24 constellations which is pretty impressive. In this blog we have another 7 to help build your knowledge of the night sky.
Sagittarius lies in the southern sky at the centre of the Milky Way, so the area is really dense in stars which makes it harder to make out this constellation. It sits low on the horizon in the northern hemisphere so is best seen after midnight in the middle of summer in July and August. Sagittarius also contains an asterism known as the Teapot which is formed by some of the brightest stars in the constellation and is easier to identify than the whole of Scorpius. The spout points to the Milky Way so it looks like there is steam coming from the spout.
In Greek mythology, Sagittarius means archer in Latin and the constellation is shown as a centaur drawing a bow towards Antares, the red star at the heart of Scorpius. The constellation depicts Crotus, a satyr who was the son of Pan and the nymph Eupheme, who was the nurse to the nine Muses (who were daughters of Zeus). Crotus and the Muses grew up together and when the Muses sang, Crotos would clap to show his appreciation and so invented applause. Crotos was known as a hunter and invented archery as well as the use of torches to hunt at night. When he died, the muses wanted to honour him, so they asked their father to place him in the stars.
The Greeks were not the first to identify Sagittarius, in Babylonian mythology, Sagittarius is associated with the centaur-like god Nergal, who is depicted with two heads – one human and one panther – and also wings, and the tail of a scorpion positioned above a horse’s tail. Nergal was a god of battle, plague and devastation who ruled the underworld alongside Ereshkigal, the queen of the dead. He wasn’t the ruler of the underworld by choice, the gods decided to hold a banquet in the heavens, but Ereshkigal could not go because she was unable to leave the underworld. So, she sent a messenger to receive her portion of the feast. When the messenger arrived, Nergal disrespected him by refusing to rise in respect and this infuriated Ereshkigal who demanded that Nergal be sent to the underworld to answer for his poor behaviour. As Nergal descended to the underworld he is slowly stripped of his armour and weapons as he passes through a series of 7 gates. When Ereshkigal saw him, she was captivated by his power and beauty, they become lovers and Nergal stays with her for 6 days and nights. Maybe Nergal was not as enamoured of Ereshkigal as she was with him, and he left the underworld without permission. She was not happy about this and was heartbroken. We know what happens when someone is scorned… they threaten to unleash the dead upon the world unless their true love returns asap! To stop this, the other gods persuaded Nergal to return to the underworld and sit alongside his lover maintaining the boundary between the living and the dead.
Serpens and Ophiuchus - these two constellations, best seen from June to August, are found in the southern sky and are best described together as Serpens, the serpent, is divided by Ophiuchus, the snake bearer. The two parts of Serpens are Serpens Caput which represents the head and Serpens Cauda, the tail.
In Greek mythology Ophiuchus represents Asclepius a famous healer, and the son of Apollo, who is holding Serpens in his arms and entwined around his waist. Asclepius was taught the art of healing by the centaur Chiron and was given the blood of Medusa by Athene. The blood from the left side of Medusa was poisonous but the blood from her right side was able to bring people back to life. As a result, Asclepius was able to bring people back to life. Another story, and the one that links Ophiuchus with Serpens was that he watched a serpent use healing herbs to save the life of another that had been killed by Asclepius when it had tried to interfere with the body of Glaucus, the son of King Minos of Crete, after he fell into a jar of honey and drowned. Asclepius then used the same herb on Glaucus who was then resurrected.
Another story is told of how Asclepius bought Hippolytus, the son of Theseus, back to life after he was thrown from his chariot. Hades was concerned that if Asclepius kept resurrecting people, there would be no more people going to hell and complained to Zeus that humans would become immortal if Asclepius was able to heal them. So, to keep his brother happy, Zeus then struck Asclepius down with a lightning bolt. He must have felt this was a bit unfair because Zeus later set Asclepius in the stars in recognition of his virtue and healing powers... and maybe to keep his son (Apollo) happy!
Scorpius can be best seen in June and July in the southern sky and represents the scorpion that killed Orion (see Star Lore 3), which is why it is set in the opposite side of the sky, chasing Orion by rising when Orion is setting. The most visible star is Antares, the red supergiant which is about 400 time larger than our sun.
This cluster of stars has been recognised as a scorpion for a long period of time, well before the Greeks or even the Mesopotamians. There is a site in modern day Turkey called Gobekli Tepe that is thought to be a temple site built by hunter gatherers (i.e. pre-agricultural society) around 10,000BC. One of the pillars on the site, called the Vulture Stone includes several animal symbols around a scorpion. It seems that if the scorpion is taken as the constellation Scorpius, then the animals appear to be in the correct positions to match the relative positions of a number of constellations.
Scorpius forms part of “the Canoe of Tamarereti” in Maori cosmology. A very long time ago, soon after the first people were placed on the Earth, there were no stars in the sky at night. It was so dark that it was impossible for people to walk around outside without tripping into things and there were taniwha, very powerful guardians of nature, who liked to feed at night on anything that moved and spent their days asleep at the bottom of lakes and in deep rivers. Tamarereti was a young warrior who lived near Lake Taupo. Tamarereti knew the taniwha would eat him if he went fishing after dark. At the time, the sky was black with no stars, but Tamarereti thought he had plenty of daylight to go fishing so he pushed his canoe out onto the lake. He caught three fish and was heading to the shore to cook his catch when his canoe was becalmed. As he waited for the wind to push him back to shore, he slept. When he awoke, he found his canoe had drifted to the opposite side of the lake. He knew he was in big trouble, it was dark, and he was far from his village. He was hungry, so he made a fire and cooked and ate the three fish. As he stood on the edge of the lake, he noticed the lake’s pebbles were reflecting the bright light of his fire, so he collected some of the pebbles and set off home tossing the shiny pebbles into the sky to light his way, and so creating the stars. Their light saved him from the water monster and the wake from his canoe formed the Milky Way.
When he got home, he slept, but woke to find Ranginui, the god of the sky, sitting by him. Tamarereti was terrified that he would be punished for spoiling the perfect blackness of the sky, but Ranginui was delighted by the beauty of the night sky and people would be able to see and move around at night. So that people would remember how the stars were made, Ranginui anchored Tamarereti’s canoe up into the brightest part of the sky.
In Navajo culture, the end curve of the tail of Scorpius was called Gah Hahat’ee and represented running rabbit tracks (see the red stars in the picture). Navajo hunters could then use these stars to determine when the traditional hunting season would begin. When the rabbit tracks remained upright, young deer still depended on their mothers for milk, so deer were not hunted. When the stars tipped to the east, it was then permitted to hunt the deer.
Libra is found lying in the southern sky between Virgo and Scorpio and is best viewed in the early summer from May until July. It is quite faint, so a dark sky is key to observing it, but as it contains Methuselah, the oldest star in our universe dated at about 14.46 billion years old (give or take 800 million years), it is worth trying to spot. Libra once formed part of the claws of Scorpio but was changed by the Romans into its own constellation in the first century when they adopted the 12-month calendar. Libra is Latin for the weighing scales and is the only sign of the zodiac that is an inanimate object.
While the Greeks do not have any myths surrounding it as a constellation, the Babylonians did associate it with scales too, naming it Zibbananna which translates as the Balance or Point of Balance and seems to refer to the time period when as Libra marked the autumn equinox in which the length of the day and night are equal. This was the case around 2,000BC, but due to precession – the shift in the Earth’s axis – the autumn equinox now occurs in Virgo. The scales were sacred to the Mesopotamian sun god Shamash who could see everything that happened in the world and was therefore responsible for truth and justice.
Bootes is seen towards the northern sky but is not seen all year round. It is not visible during the evening in the late autumn and winter, rising in March and setting in late August / early September but is most visible from April through to July. The constellation includes the star Arcturus which is one of the brightest in the northern hemisphere. Finding Arcturus and therefore Bootes is easy, follow the arc of the Plough handle and carry on until you reach Arcturus – Arc to Arcturus.
There seems to be a few Greek origin stories associated with Bootes. One of them is linked to Canis Minor (Star Lore 3). In that myth, Bootes represents Icarus of Athens a farmer that was taught how to make wine by Dionysus. Icarius, the first human to make wine, invited some shepherd friends to drink with him at his farmhouse and they all fell over blind drunk and fell asleep. The next morning heralded the invention of the hangover! The shepherds woke with massive headaches, vomiting and feeling just like they had been poisoned, so they murdered Icarius in their believing he had tried to kill them. They hid his body in a ditch. Icarius’ faithful dog Maera went to find his daughter Erigone and showed her where Icarius’ body lay hidden. She was so grief-stricken that she hung herself. While Maera jumped off a cliff. Dionysus was so angry that he punished Athens with a drought and inflicting insanity on all the unmarried women, who all hanged themselves, imitating Erigone. Dionysus placed Icarius, Erigone and Maera in the sky as the constellations Bootes, Virgo, and Canis Minor.
In another myth, Bootes is taken to represent Arcas, the son of Zeus and Callisto the daughter of King Lycaon. Zeus had transformed himself into a likeness of Artemis who Callisto worshipped to have his wicked way with her. When Zeus’s wife Hera found out about his tryst, she turned Callisto into a bear and so Arcas was raised by his grandfather King Lycaon. One day, Zeus visited Lycaon for a meal, but the king decided to test Zeus by serving him Arcas as the meal. Zeus realised what was happening and was so angry he turned Lycaon into a wolf, killed his sons with thunder bolts and bought Arcas back to life where he became a great hunter. Meanwhile, Callisto – his mother – was living as a bear in the woods. One day, Arcas went hunting and not recognising his mother started hunting her. She hid in a temple so that he could not kill her, and to avoid the worst from happening, Zeus placed them both in the sky to keep them safe. Callisto as Ursa Major and Arcas as Bootes. This story fits well with the name of the star Arcturus because it comes from the Greek arktouros meaning ‘guardian of the bear’. However, in one version, Arcas is placed in the sky as Ursa Minor!
In another Greek story, Bootes is the herdsman that invents the plough and is placed in the sky by the goddess Ceres which also fits quite nicely with its position with the Plough which the ancient Greek poets (including Homer) also saw an asterism as a cart with oxen alongside seeing the wider constellation as a bear.
Corona Borealis meaning northern crown, is a semi-circular arc formed of 7 stars that is found between Hercules and Bootes. It is mainly visible from March until September in the UK and is most easily seen around midnight during June when it sits high in the sky.
In Greek mythology, Corona Borealis was linked to the legend of Theseus and the minotaur. After Theseus had been helped by Ariadne, the daughter of King Minos of Crete to get out of the Labyrinth after he had killed the minotaur, they fled Crete together to the island of Naxos where the dastardly Theseus abandoned her because he fell in love with another woman. She was found by Dionysus, the god of wine, fertility, and wild parties, who fell in love with her. They married and during the wedding Ariadne wore a crown, made by Hephaestus, and given to her by Dionysus. After the wedding, Dionysus cast the crown into the heavens to symbolise their marriage and her immortal status.
There is a slightly different and less known version of the story which Ariadne not only gives Theseus the thread but also the crown, which was a gift from Dionysus. Theseus uses the crown’s light to escape the labyrinth after killing the minotaur, and to celebrate the event, Dionysus later set it in the sky.
Various Native American people had myths associated with Corona Borealis. The Skidi people, members of the Pawnee Nation, believe that it represented a council of stars whose chief was Polaris. The constellation also symbolised the smoke hole over a fireplace, which conveyed their messages to the gods, as well as how chiefs should come together to consider matters of importance.
The Shawnee believed that the stars represent seven Heavenly Sisters. A mighty hunter named White Hawk is searching for game when he comes across a circular path worn into the grass on a prairie, but he cannot find any tracks leading to or from it. Curious, he hid nearby to watches and soon, seven beautiful celestial sisters descend from the sky in a silver basket and begin to dance in the circle. White Hawk falls in love with the youngest sister but when he tried to capture her, all the celestial sisters jump back into the basket and ascend into the sky. The next day, he revisits the spot disguised as a rabbit to lure her away but that does not work. The day after, he tries again in the guise of a mouse, and he successfully captures the most beautiful sister and takes her to his village to become his bride. Eventually, she misses her sisters and weaving a sliver basket and chanting a song, she returned to the sky, joining them once more as Alphecca, the brightest of the seven stars of Corona Borealis.
Several Algonquian speaking people have traditions that associate Corona Borealis as the den of a celestial bear being pursued by hunters in the summer - which is represented by some of the stars in Ursa Major. As the season changes to autumn, the bear is said to be wounded by the hunters, and this is seen as the red leaves of autumn. After being struck, the bear retreats into its den for safety which is symbolised by the Corona Borealis and reflects the winter hibernation where there is rest and renewal.