Introduction: A Gateway to the Stars

http://www.istockphoto.com/stock-photo-30879072-starry-sky.php?st=80a59b5

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?

http://commons.wikimedia.org/wiki/File:Orion_Head_to_Toe_-_Reduced.jpg

Orion the hunter, bathing in the blood of his victims. Or a nebula. You decide.

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.

http://www.istockphoto.com/stock-photo-684872-airbrushed-night-sky-with-the-plough-and-great-bear-constellat.php

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?

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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.

http://www.iau.org/public/themes/constellations/

Source: International Astronomical Union

http://commons.wikimedia.org/wiki/File:Pleiades_large.jpg

If you rotate it clockwise it resembles the dots over the aurochs’ back. I did say it required some imagination.

Eastern Promise

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.

http://upload.wikimedia.org/wikipedia/commons/0/0f/HerculesCC.jpg

Hercules, possibly the happiest of constellations.

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.

Grecian Completion

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!

http://commons.wikimedia.org/wiki/File:Claudius_Ptolemaeus.jpgPtolemy, 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?

Southern Skies

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?

http://commons.wikimedia.org/wiki/File:Orion_Head_to_Toe_-_Reduced.jpg

Star trails over Kozani, Greece, by Nikos Koutoulas.

Star Trail

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 –

http://commons.wikimedia.org/wiki/File:Crux_constellation.png

will never be visible as it will never rise above the horizon, and likewise the Little Bear – Ursa Minor –

http://commons.wikimedia.org/wiki/File:UrsaMinorCC.jpg

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.”

http://www.istockphoto.com/stock-photo-28188344-telescope-and-starry-sky.php?st=bdf147f

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.

http://en.wikipedia.org/wiki/User:Dna-webmaster

Source: Dna-webmaster

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.

http://commons.wikimedia.org/wiki/File:AstroDeclinationRightascension.png

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.

Further Illumination

http://commons.wikimedia.org/wiki/File:Sirius_A_and_B_Hubble_photo.jpg

Sirius A, the brightest star in the sky and part of the constellation the Great Dog, otherwise known as Canis Major.

Apparent Magnitude

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.

http://commons.wikimedia.org/wiki/File:The_bright_star_Alpha_Centauri_and_its_surroundings.jpg

Alpha Centauri. Source: European Southern Observatory

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.

http://commons.wikimedia.org/wiki/File:Constellation-art-pegasus.png

Pegasus, by Johan Meuris

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

Name  Abbr. English Name Genitive Hemisphere
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
Aquila Aql the Eagle Aquilae Northern
Ara Ara the Altar Arae Southern
Aries Ari the Ram Arietis Northern
Auriga Aur the Charioteer Aurigae Northern
Bootes Boo the Herdsman Bootis Northern
Caelum Cae the Engraving Tool Caeli Southern
Camelopardalis Cam the Giraffe Camelopardalis Northern
Cancer Cnc the Crab Cancri Northern
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
Carina Car the Keel Carinae Southern
Cassiopeia Cas the Seated Queen Cassiopeiae Northern
Centaurus Cen the Centaur Centauri Southern
Cepheus Cep the King Cephei Northern
Cetus Cet the Sea Monster Ceti Southern
Chamaeleon Cha the Chameleon Chamaeleontis Southern
Circinus Cir the Compass Circini Southern
Columba Col the Dove Columbae 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
Corvus Crv the Crow Corvi Southern
Crater Crt the Cup Crateris Southern
Crux Cru the Southern Cross Crucis Southern
Cygnus Cyg the Swan Cygni Northern
Delphinus Del the Dolphin Delphini Northern
Dorado Dor the Swordfish Doradus Southern
Draco Dra the Dragon Draconis Northern
Equuleus Equ the Little Horse Equulei Northern
Eridanus Eri the River Eridani Southern
Fornax For the Furnace Fornacis Southern
Gemini Gem the Twins Geminorum Northern
Grus Gru the Crane Gruis Southern
Hercules Her Hercules Herculis Northern
Horologium Hor the Clock Horologii Southern
Hydra Hya the Female Water Snake Hydrae Southern
Hydrus Hyi the Male Water Snake Hydri Southern
Indus Ind the Indian Indi Southern
Lacerta Lac the Lizard Lacertae Northern
Leo Leo the Lion Leonis Northern
Leo Minor LMi the Lesser Lion Leonis Minoris Northern
Lepus Lep the Hare Leporis Northern
Libra Lib the Scales Librae Southern
Lupus Lup the Wolf Lupi Southern
Lynx Lyn the Lynx Lyncis Northern
Lyra Lyr the Lyre Lyrae Northern
Mensa Men the Table Mountain Mensae Southern
Microscopium Mic the Microscope Microscopii Southern
Monoceros Mon the Unicorn Monocerotis Northern
Musca Mus the Fly Muscae Southern
Norma Nor the Carpenter’s Square Normae Southern
Octans Oct the Octant Octantis Southern
Ophiuchus Oph the Serpent Bearer Ophiuchi Northern
Orion Ori the Hunter Orionis Northern
Pavo Pav the Peacock Pavonis Southern
Pegasus Peg the Winged Horse Pegasi Northern
Perseus Per the Hero Persei Northern
Phoenix Phe the Phoenix Phoenicis Southern
Pictor Pic the Painter’s Easel Pictoris Southern
Pisces Psc the Fishes Piscium Northern
Piscis Austrinis PsA the Southern Fish Piscis Austrini Southern
Puppis Pup the Stern Puppis Southern
Pyxis Pyx the Compass Pyxidis Southern
Reticulum Ret the Reticle Reticulae Southern
Sagitta Sge the Arrow Sagittae Northern
Sagittarius Sgr the Archer Sagittarii Southern
Scorpius Sco the Scorpion Scorpii Southern
Sculptor Scl the Sculptor Sculptoris Southern
Scutum Sct the Shield Scuti Southern
Serpens Ser the Serpent Serpentis Northern
Sextans Sex the Sextant Sextantis Southern
Taurus Tau the Bull Tauri Northern
Telescopium Tel the Telescope Telescopii Southern
Triangulum Tri the Triangle Trianguli Northern
Triangulum Australe TrA the Southern Triangle Triangulii Australis Southern
Tucana Tuc the Toucan Tucanae Southern
Ursa Major UMa the Great Bear Ursae Majoris Northern
Ursa Minor UMi the Little Bear Ursae Minoris Northern
Vela Vel the Sails Velorum Southern
Virgo Vir the Maiden Virginis Southern
Volans Vol the Flying Fish Volantis Southern
Vulpecula Vul the Fox Vulpeculae Northern

Sources

http://www.istockphoto.com/stock-photo-23846374-map-of-stars.php?st=0531b8f

1. AUJOULAT, N. (2005) The Astronomical Rock Panels in the Lascaux Cave, France. Portal to the Heritage of Astronomy. Available from: http://www2.astronomicalheritage.net/index.php/show-entity?identity=5&idsubentity=1 [Accessed 31/01/2014]

2. CLARK, S. (2010) Voyager: 101 Wonders Between Earth and the Edge of the Cosmos. London: Callisto and Atlantic Books.

3. MOORE, P. (2007) Atlas of the UniverseSixth Edition. London: Philip’s.

4. OWEN, S. (2013) Stargazing for Dummies. Chichester: John Wiley & Sons, Ltd.

5. SPARROW, G. (2013) Constellations: A Field Guide to the Night Sky. London: Quercus.

6. SPARROW, G. and STOTT, C. (2013) Planisphere and Starfinder: The Complete Beginner’s Guide to Exploring the Night Sky. London: Dorling Kindersley.

7. WHITEHOUSE, D. (2000) Oldest Lunar Calendar Identified. BBC. Available from: http://news.bbc.co.uk/1/hi/sci/tech/975360.stm [Accessed 08/02/2014]

8. Encyclopaedia Britannica (n.d.), Constellation. Britannica.com. Available at: http://www.britannica.com/EBchecked/topic/134125/constellation [Accessed 31/01/2014]

9. Encyclopaedia Britannica (n.d.), Ptolemy. Britannica.com. Available at: http://www.britannica.com/EBchecked/topic/482098/Ptolemy [Accessed 31/01/2014]

10. I.A.U. (n.d.) The Constellations [Online] I.A.U. Available from: http://www.iau.org/public/themes/constellations/[Accessed 02/02/2014]

11. I.C.Q. (n.d.). The Astronomical Magnitude Scale. The ICQ Comet Information Website. Available from: http://www.icq.eps.harvard.edu/MagScale.html [Accessed 13/02/2014]

12. I.N.F.I.S. (n.d.).The Pleiades in the „Salle des Taureaux“, Grotte de Lascaux. Does a Rock Picture in the Cave of Lascaux Show the Open Star Cluster of the Pleiades at the Magdalenian era (ca 15.300 BC)? I.N.F.I.S. Available from: http://www.infis.org/downloads/mr1997cenglpdf.pdf [Accessed 31/01/2014]

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