Learning about the constellations not only gives you a taste of human history, astronomy and the enormity of the cosmos, but a comforting feeling of familiarity. Being able to look up at the night sky, decode the jumbled celestial glitter and navigate your way home can imbue you with a sense of satisfaction, and dare I say it even smugness. Especially if your phone/sat-nav/compass ever decided to die.
Before embarking on a journey through each and every constellation and its history, legend and celestial make up, I thought I would start from the ground up and take a look at these starry patterns as a whole. For an amateur-amateur astronomer like me, no question is too obvious here, so first and foremost:
What Are Constellations?
Constellations are specific stars that were grouped together because they made a certain shape in the sky. At least according to the people who named them. These shapes can range from the fantastical (Draco the dragon) to the mundane (Telescopium, the telescope. Seriously.), and much like playing the cloud game of an afternoon, a fair amount of imagination is involved.
What’s more, a constellation isn’t just any old arrangement of stars. For example, have you heard of The Plough (or Big Dipper if you’re from across the pond)? Allow me to blow your mind by revealing that it’s not a constellation. It’s actually part of the Great Bear – Ursa Major – and is what’s known as an asterism. Since The Plough constitutes the rear end of said bear, I’ll leave you to decide if that name’s more appropriate than normal.
Moving swiftly on, there are 88 constellations in total, and every visible star in the sky is mapped to a constellation, even if it doesn’t form part of its official shape. For example, our friend Ursa Major is the subject of the image above, but any stars within the picture frame may also be described as part of the Ursa Major area.
The borders of each constellation area as well as their official name and shape were compiled in 1930 by the International Astronomical Union. A chap named Eugène Delporte helpfully listed them on behalf of the Union in his tome Délimitation scientifique des constellations, and I’ve included a table of them at the very end of this post to spare you line hypnosis from scrolling down.
Of course, the I.A.U. didn’t just look up at the sky one night and decide there and then how to name the stars. So with this in mind,
Who Named the Constellations?
Since antiquity, various civilisations have seen patterns and stories in the stars and tried to make sense of what they were seeing, making the answer to this question a tad complicated.
Cave of Wonders
The earliest recorded sign of humans using the stars for time-keeping or making pretty pictures is some 17,000 years ago, in the Lascaux cave paintings in southern France. This is still open for debate, but there are some suspiciously celestial markings on display, like the one above an aurochs in the Hall of Bulls similar to the asterism Pleiades. Pleiades being, coincidentally, part of the modern constellation Taurus.
The ancient Egyptians and Chinese also had their own ways of interpreting the stars, but the constellations we know and love today (or will grow to love, if my blog does its job) are based on those from Ancient Greece.
In turn, thanks to deciphering certain cuneiforms – ancient Middle Eastern writing systems – it’s recently been discovered that the Greeks adapted most, if not all of the modern constellations, from those of ancient peoples in the Euphrates area in western Asia, such as the Sumerians and Mesopotamians. That’s right, the ones who purportedly worshipped Zuul, so they would know their stuff when it comes to celestial monsters. At least according to the Ghostbusters.
Here’s another ancient reference for you; the earliest known Greek compendium of constellations is the Phaenomena, by Eudoxus of Cnidus, which was written around 350 BC. Sadly, this has been lost to the years, but Aratus, a poet of the King of Macedonia, was kind enough to preserve it in verse form.
This collection was then ruthlessly nit-picked in a commentary by the astronomer and mathematician Hipparchus, whose other works also had a knack for vanishing before historians could get their hands on them. Nonetheless, Hipparchus’ work forms the basis of our final milestone; the Almagest, a thirteen volume major astronomical work by Egyptian astronomer, mathematician and geographer, Ptolemy, which was composed around the year 150. At least we’ve crossed into positive numbers now!
Ptolemy, whose full name was Claudius Ptolemaeus of Alexandria, was the proponent of the sun and planets revolving around the Earth and was convinced that said movement of the sun, planets and stars could be explained mathematically. Obviously his ideas about the sun’s rotation weren’t quite right, and later astronomers such as Brahe cast some doubt as to whether he did all the homework he said he did regarding which stars he spotted and where. However, his collection, originally named Mathematike Syntaxis (“The Mathematical Arrangement”), formed the backbone of European and Islamic astronomy right up until the 17th Century. Books seven and eight of the Almagest made up the star catalogue, but the entries were restricted to whichever stars Ptolemy could see from the skies of Egypt. The result? Only 48 constellations were recorded. So where did the remaining 40 come from?
Most of the other modern constellations were drawn up by European explorers and astronomers as they ventured south of the Equator. Some major contributors to modern day star charts were three Dutch navigators Pieter Dirkszoon Keyser, Frederick de Houtman and Gerard Mercator and their followers in the 1600s, and French astronomer Nicolas Louis de Lacaille who patched up the remaining gaps of sky around 1763.
Not all submissions were accepted, mind: ‘The Balloon” and the equally fascinating “Printing Press” have since been cast from the skies, and one of the more cumbersome of Ptolemy’s creations, “Argo Navis” – the boat that Jason and the Argonauts sailed on – has been dissected into the more manageable Carina (keel), Puppis (poop, as in deck) and Vela (sails).
That pretty much explains how the constellations came about, but how can you spot them?
Apart from just looking up, smarty pants.
Where Can You Find The Constellations?
Due to the curvaceous nature of our planet and its suggestive tilt, twirl and continuing dance around the sun, not all of the constellations are visible to everyone at any one time.
For instance, for those in the northern hemisphere, the famous Southern Cross – Crux –
will never be visible as it will never rise above the horizon, and likewise the Little Bear – Ursa Minor –
which contains the pole star Polaris, only scrapes the very top of the southern hemisphere. This is due to the bulk of the Earth being in the way whenever you look up or ahead, depending on where you are on the planet.
Some constellations will also only be visible at certain times of year depending on your respective hemisphere, again due to the lumps and bumps of the Earth and its journey as described above. The constellations which aren’t spoilsports and are visible all year round are known as circumpolar.
For each entry I’ll include where and when you can spot each constellation, but if you’re not a stargazer, you can hop, skip and jump over the next section and head to “Further Illumination”. If you do want to grab a telescope and see the patterns for yourself, I hope this next part is helpful.
“Six hours, nineteen minutes, right ascension, fourteen degrees, fifty-eight minutes declination! …no sighting.”
If you have any knowledge of stargazing, or like me caught the Simpsons episode where Principal Skinner drags Bart out in the early hours to look through a telescope, you’ll have heard the terms “declination” and “right ascension“. Loosely speaking these are stand-ins for latitude (up/down) and longitude (across. I’m specifying this for my own benefit because I sometimes forget, not because I think you’re an idiot).
When it comes to towns, cities and other Earth-based points of reference, you can locate them via their latitude and longitude coordinates, essentially an x and y axis. This is possible because any designated place on the ground tends to stay in one place, so it’s easy to refer to any other locations as a certain number of degrees north, south, east or west of that point.
Naturally, this is more complicated when it comes to the sky because everything is moving about, and so finding somewhere to mark as “o°” is trickier.
The ancient Egyptians thought that there was a celestial sphere surrounding the Earth which contained all the stars and planets, so for simplicity’s sake (for a change), astronomers decided to go with this idea when sorting out how to reference stars in the night sky. So, the Earth also has a Celestial Equator, which shockingly mirrors the actual Equator. The north and south poles have a celestial equivalent as well (if a couple of degrees off), and the path of the sun through the sky is known as the ecliptic, as you can see below.
Celestial latitude is known as declination. The Celestial Equator is used to mark oº because its position never changes, so if an object is north of the Celestial Equator, its declination is given as xº or xºN; if it’s south, it would either be -xº or xºS.
You can find out if a star is circumpolar, visible or invisible from where you are if you subtract your position from 90, because 90º marks the North Pole. So for example, if London is at 51°, 90 – 51 is 39. Therefore, any stars of 39º declination or above will always be above the horizon. Any with a declination south of -39º would never rise above the horizon. Any stars in between would appear above the horizon at some point.
Unfortunately, longitude isn’t quite as co-operative.
The point at which the ecliptic (the sun’s path) crosses the Celestial Equator is known as the Vernal Equinox, or First Point of Aries. As usual, this point is no longer within the constellation of Aries due to the stars and Earth shifting about over the years, but you get the idea. This is the position used to measure celestial longitude, which is known as right ascension.
To further complicate matters, an objects’s right ascension is measured in time rather than degrees.
When a star reaches its highest point in the sky during a 24 hour period, this is known as its culmination. The time it takes to reach its culmination from the First Point of Aries is its right ascension. So when Principal Skinner babbles excitedly about “sixteen hours nineteen minutes right ascension”, it means the object he is looking at takes this amount of time to move across the sky from the First Point of Aries to its highest point (culmination).
As the seldom-used mathematical part of my brain smokes, I should make it clear that this blog will mainly focus on constellation facts rather than stargazing as a whole, so you may need to wander briefly away if you need more detailed advice about picking the best telescope/binoculars and so on. I may include more about this equipment in future, as I’m currently awaiting the arrival of my own first telescope, but I hope the above sheds some light on where to look in the evenings.
Incidentally, when stargazing, unless you’re planning to gape at the moon it’s best to choose a night without one, not only to reduce the risk of werewolf attack but so that its light doesn’t drown out the stars. Picking a spot with less light pollution would also be a good move. Talking about light conditions also gives a handy segue into the next section.
When looking at stars astronomers will talk about their “apparent magnitude”, and this is how bright a star or object is when seen with the naked eye. The brighter it appears, the lower its score, so for example the Sun has an apparent magnitude of -26; a full moon -13, and for stars or objects just about visible to the naked eye, an apparent magnitude of 6.
Why is this important? The stars within a constellation are usually classified and ordered according to their apparent magnitude. Rather than ordering by number, astronomers use the Greek alphabet, so the star “Alpha Centauri” (shown above) refers to the brightest star in the constellation Centaurus, as alpha is the first letter. If that weren’t enough to wrap your head around, this isn’t always done in order either: the brightest star in Sagittarius is in fact marked as epsilon (the fifth letter), whereas the alpha and beta (second letter) labelled stars are much fainter. You can thank German astronomer Mr. Johann Bayer and his 1603 star catalogue for this.
A more number-friendly system was devised later in the 17th Century by John Flamsteed, an Astronomer Royal, and his numbers are still used today, especially when designating other stars or deep space objects outside of the main constellation pattern. As for the constellations themselves, appearances can be deceptive, and I don’t just mean how they never seem to resemble their names.
Line of Sight
When someone looks up at the night sky they only see a 2D version of space. This means that stars in a constellation might seem close to one another but could in fact be thousands of light years apart.
Imagine you’re at the front of a queue of people. If you look back at the queue, the head of the person at the very end may only appear a few centimetres further away than that of the person directly behind you. But if you stepped out of the queue to see it side on, these people would be several metres apart.
So in essence, Earth is at the front of the queue and has a specific view of the stars surrounding it, whereas any aliens or space debris facing from another angle would see an utterly different arrangement.
So far we’ve covered what constellations are, how they were created and the basics of how they can be referenced and catalogued in the sky. Before diving into each and every one, there is a burning issue to address – the types of celestial objects that bring them to life. Far from being vague pinpoints, these can be world-eating or star-birthing forces of nature, so they’re more than worthy of attention before embarking on a trek through the constellations. I hope you’ll follow me to my next post where they’ll be given an opportunity to shine. Well, more than my attempts at puns anyway.
In the interim, below is the possible bout of line hypnosis: a table of all 88 official constellations followed by my sources.
Thanks for reading!
List of the 88 Modern Constellations
|Andromeda||And.||the Chained Maiden||Andromedae||Northern|
|Antlia||Ant.||the Air Pump||Antliae||Southern|
|Apus||Aps||the Bird of Paradise||Apodis||Southern|
|Aquarius||Aqr||the Water Bearer||Aquarii||Southern|
|Caelum||Cae||the Engraving Tool||Caeli||Southern|
|Canes Venatici||CVn||the Hunting Dogs||Canum Venaticorum||Northern|
|Canis Major||CMa||the Great Dog||Canis Majoris||Southern|
|Canis Minor||CMi||the Lesser Dog||Canis Minoris||Northern|
|Capricornus||Cap||the Sea Goat||Capricorni||Southern|
|Cassiopeia||Cas||the Seated Queen||Cassiopeiae||Northern|
|Cetus||Cet||the Sea Monster||Ceti||Southern|
|Coma Berenices||Com||the Bernice’s Hair||Comae Berenices||Northern|
|Corona Australis||CrA||the Southern Crown||Coronae Australis||Southern|
|Corona Borealis||CrB||the Northern Crown||Coronae Borealis||Northern|
|Crux||Cru||the Southern Cross||Crucis||Southern|
|Equuleus||Equ||the Little Horse||Equulei||Northern|
|Hydra||Hya||the Female Water Snake||Hydrae||Southern|
|Hydrus||Hyi||the Male Water Snake||Hydri||Southern|
|Leo Minor||LMi||the Lesser Lion||Leonis Minoris||Northern|
|Mensa||Men||the Table Mountain||Mensae||Southern|
|Norma||Nor||the Carpenter’s Square||Normae||Southern|
|Ophiuchus||Oph||the Serpent Bearer||Ophiuchi||Northern|
|Pegasus||Peg||the Winged Horse||Pegasi||Northern|
|Pictor||Pic||the Painter’s Easel||Pictoris||Southern|
|Piscis Austrinis||PsA||the Southern Fish||Piscis Austrini||Southern|
|Triangulum Australe||TrA||the Southern Triangle||Triangulii Australis||Southern|
|Ursa Major||UMa||the Great Bear||Ursae Majoris||Northern|
|Ursa Minor||UMi||the Little Bear||Ursae Minoris||Northern|
|Volans||Vol||the Flying Fish||Volantis||Southern|
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