Introduction to ConstellationsBackyard Astronomy

Warm Up

1. What is a constellation?

2. What is a circumpolar constellation?

3. Around what point do all the stars rotate?

4. How do you locate Polaris?

5. Name four things that make stargazing more comfortable?

The Night SkyPeople have watched the night skies for millions of years. Some just out of curiosity. Some out of boredom. Some looking for portents, either good or bad.

However, the one thing that they all saw was that there was a pattern in the way the stars revolved around the heavens.

The Night Sky

You need only to look up for a few hours to begin to see these same patterns yourself. Like the Sun, stars rise in the east and set later in the west. Planets follow this same pattern unless they are in a retrograde period, though these periods are not especially common.

What You Need for Stargazing

You don’t really need anything, but some things are handy, like…

Complete darkness-Don’t laugh, it’s not that easy to find. Rural area are slowly being urbanized, bringing their lights with them. Light pollution is a real problem.

What You Need: Darkness

Darkness means getting away from the city when you can. Crowder’s Mountain, South Mountain, The Blue Ridge Parkway and several rural spots outside Matthews and Huntersville are still fairly dark. I recommend the Parkway in the Fall and Winter. The quantity of stars you see will take your breath.

What You Need: Darkness

Darkness means keeping up with the phases of the moon, too. When the moon is waxing past half full, it’s quite hard to see.

What You Need: Star Map/ Planesphere

It is handy to have a star map to help get you oriented. We will make one in here, so you get the idea, but laminated ones are nice and they are protected from dew and spilled drinks when your tripping around in the dark. Star Maps are also called planespheres. You can find them in hobby stores for a couple of bucks.

What You Need: Flashlight

Well, you don’t have to trip around in the dark. You can bring a flashlight! There’s one problem here though. It takes your eyes about 20-30 minutes to get acclimated to the dark. Your pupils aren’t fully dilated until then, so a regular flashlight will never do. Your eyes will have to get acclimated every time you turn it on. To prevent this, your flashlight should have a red gel to protect your eyes. Red saran wrap with a rubber band works great . It works great for catching night crawlers too.

What You Need: Binoculars

Binoculars don’t have to be very strong to give you a much better, brighter view of the stars. Binoculars have the ability to gather light even at low magnifications. Even 4X ones will make a marked difference in the detail you can see.

What You Need: Telescope?

No, you don’t need a telescope, though they are fun. Telescopes require a certain amount of sophistication to set up and operate and they are not for everybody. There are some nice models available at affordable costs. The optics are available alone also if you want to build your own.

What You Need: Warm ClothesYou’ll be happy to know that the best time to look at stars is the least popular time of year to be outside, the winter. So, dress warmly. Remember that the nights are longer in the winter.

Leonid: An AsideI remember the 2002 Leonid meteor shower very well. The Leonid comes in November and that year it was really cold. I got up about 3:30 a.m. (yes, that’s right) to have a look. It was incredible. Meteors were streaking across the sky every few seconds. Sometimes several at once. It was the best Leonid for over 35 years. I even woke my wife up to join me. We sat on the deck in sleeping bags and drank coffee. It’s one of my happiest memories. Another Leonid of that magnitude is not expected again until 2098 or 2131.

Finding Polaris and Why

Polaris (or the North Star) is where you want to start. Because Polaris is aligned with the Earth’s axis of rotation, it remains fixed, with all the other planets and stars appearing to move around it. It is the one star that remains fixed at all times.

Getting Oriented or Where the Hell is North?

Yea, you have to find north. It’s where Polaris (or North Star) is. You’ll need a compass or major highway to orient yourself. I-77 is good because it runs due north and south. You can make a compass with a needle, magnet and a cup of water. Just rub the needle across a magnet (see your refrigerator) or leave it attached overnight. Then rub the needle across your nose and place it in the cup very gently. It will float. It will turn north.

Figuring the AngleOnce you’ve decided where north is (right ascension), face in that direction. Next you have to figure declination (up and down). Extend your arm and make a fist. Put the bottom of your fist on the horizon. The top of your fist is about 80 higher. Place your other fist on top of your first. You’ve now measured 160 up from the horizon. Polaris is located between 250 and 300 above the horizon. Polaris is faint, so look carefully!

Another Way to Find Polaris

If all that compass making and angle crap is just too complicated, there is another way to find Polaris. Find the Big Dipper (not a constellation). Most people recognize this asterism. The two stars that form the front of the cup of the dipper define a line pointing to Polaris.

The Big Dipper

The Stars Circling Polaris

Now That You’re Oriented, It’s Time to Explore.

You’re pointed in the right direction, but what now. Stars and constellations move constantly and seasonally. What am I looking for? What

you need is a star map.

Now That You’re Oriented, It’s Time to Explore.

You also have access to software that provides you with the same information.

Circumpolar Constellations

“Circum” means around (i.e. circumcise, circumnavigate, circumference). Polar refers to the North Pole. Therefore, circumpolar constellations circle Polaris. This makes the 5 circumpolar constellations visible throughout the entire year. Let’s look at each!

Ursa Minor

Once you’ve located Polaris, you’re ready to identify your first constellation. Polaris is the last star located in the handle of the asterism, the Little Dipper. The name of the constellation that contains the Little Dipper is Ursa Minor or Little Bear.

Ursa Minor Ursa Minor, also called the Little Dipper, is a

circumpolar constellation. This means it never sets in the northern sky. The true figure represented by the stars is the Little Bear.

There are several mythological stories behind these famous constellations. In Greek myth, Zeus was having an affair with the lovely Callisto. When his wife, Hera, found out she changed Callisto into a bear. Zeus put the bear in the sky along with the Little Bear, which is Callisto's son, Arcas.

Ursa Minor

Ursa MajorUrsa Major is probably the most famous constellation, with the exception of Orion. Also known as the Great Bear, it has a companion called Ursa Minor, or Little Bear. Everyone living in the Northern Hemisphere has probably spotted the easily recognized portion of this huge constellation. The body and tail of the bear make up what is known as the Big Dipper.

Several different cultures saw a big bear in the sky. The ancient Greeks had a few different stories to explain how the animal ended up there. In one story, Hera discovered Zeus was having an affair with Callisto and turned her into a bear. Zeus put her in the sky along with her son, Arcas, who became the Little Bear.

Ursa Major

CassiopeiaCassiopeia was the wife of King Cepheus. She was very pretty, and would often boast that she and her daughter were more beautiful than the sea nymphs, the Nereids. They complained to Poseidon, who unleashed a monster onto Cepheus' land. In order to save their country, the king and queen sacrificed their daughter, Andromeda. Just before the monster, named Cetus, ate the princess, Perseus saved her. All five figures are represented in the sky as constellations. Cassiopeia has a very distinct shape. She looks like a "W" or "M" in the sky, depending on where she is. Some legends say that Cassiopeia was chained into the sky and sometimes hangs upside-down to remind others not to be so boastful.

Cassiopeia

CepheusCepheus is one of the oldest constellations in the night sky. This house-shaped constellation is named after an ancient king of a land called Ethiopia (different from the current country, Ethiopia). He was married to the beautiful Cassiopeia and had a daughter, Andromeda. In Greek mythology, Cassiopeia boasted that she and her daughter were more beautiful than the Nereids. They complained to the sea god Poseidon, who sent a monster to destroy Cepheus' land. The king and queen offered their daughter to the monster, but she was saved by Perseus.

Cepheus

Draco Draco the dragon, is only present in the Northern

Hemisphere, so those living in the Southern Hemisphere will never see this long constellation.

The easiest way to spot Draco is by finding his head. It consists of four stars in a trapezoid, burning brightly just north of Hercules. From there, the tail slithers through the sky, eventually ending between the Big and Little Dippers. It can be difficult to trace Draco in the night sky. From the head, follow the body north towards Cepheus. It suddenly shifts south and west, ending up between the two dippers. The end of the constellation is held by Thuban, which was the pole star over 4,000 years ago.

Draco

Signs of the ZodiacCommon Constellations

Aquarius: The Water BearerIn Greek mythology Aquarius was Ganymede, "cup-bearer to the gods". Alpha Aquarii ("Sadalmelik") and beta Aquarii ("Sadalsuud") are twin supergiants with nearly identical names. The names mean, respectively, "The Lucky One of the King" and "The Luckiest of the Lucky". Gamma Aquarii shares in the good fortune: "Sadachbia": "The Lucky Star of Hidden Things" Incidentally, if the "Age of Aquarius" was celebrated in the 1960s, the real event is still some 600 years off: at that time Aquarius will contain the vernal equinox, marking the return of the Sun into the northern celestial hemisphere.

Aquarius: The Water Bearer

Aries: the Ram

Aries, "The Ram", is an ancient constellation which was of considerable importance since the sun passed through it at the vernal equinox. This point has now moved into Pisces, but the vernal

equinox is still known as the First Point of Aries. In another six hundred years the point will have moved into Aquarius.

The Ram in question may have been the one whose golden fleece was the object of Jason's quest. There is some reason to believe that the Greeks just took over a much older horned animal at this time of the year; the horn being a symbol for fecundity, renewal, and so on. As the Sun came into this constellation, at the vernal equinox, the year itself was being renewed.

Aries: the Ram

Cancer The Crab

The name comes from the Latin; cancer means crab. The crab in question is the one sent by Hydra to attack Heracles. It was only a bit part, but one which secured its immortality.

Cancer

Gemini The TwinsGemini, the Twins, are really only half-brothers. They share the same mother (Leda) but have different fathers. Castor's father was a king of Sparta, Tyndareus - who would be chased from his throne but later rescued by Heracles (who nevertheless wound up killing him). The father of Pollux was none other than Zeus, or Jupiter. Zeus visited Leda on her wedding night in the guise of a swan. Thus the twins would be born. (In fact two twins came from this double union, but let's not complicate the matter even more...)

Gemini

Leo: The LionThe first on the list of Heracles' labors was the task of killing the Nemean Lion, a giant beast that roamed the hills and the streets of the Peloponnesian villages, devouring whomever it met. The animal's skin was impervious to iron, bronze, and stone. Heracles' arrows harmlessly bounced off the lion; his sword bent in two; his wooden club smashed to pieces. So Heracles wrestled with the beast, finally choking it to death. He then wrapped the lion's pelt about him; it would protect him from the next labor: killing the poisonous Hydra.

Leo

Libra: The ScalesLibra means "The Scales" or "Balance", so named because when the zodiac was still in its infancy, some four thousand years ago, the sun passed through this constellation at the autumnal equinox (21 September). At the two equinoxes (Spring and Autumn) the hours of daylight and darkness are equal. As a symbol for equality, the constellation came to represent Justice in several middle Eastern cultures. However, the Greeks had a different perspective; at one time Scorpius, which lies just to the east, was much larger, and the stars that make up Libra were then known as the Claws of the Scorpion.

Libra

Pisces: The FishPisces is an ancient constellation derived, some say, from the story of the terrible Greek god Typhon. (This is not the Chinese word for "big wind", which

- in English - is of course spelled "typhoon". The French, however, spell this word "typhon", which adds to the confusion. It is possible that the Chinese borrowed the word from the Greek. The modern Greek equivalent is spelled "tau upsilon phi omega nu" and means "cyclone".)

Pisces

SagittariusIt was the Romans who named the constellation Sagittarius ("sagitta" is Latin for `arrow'), although several stars carry Arabic names which identify just which portion of the constellation they represent. Sagittarius has a muddled history. In ancient times the asterism of three bright stars in a curved line was seen as a bow to some, leading both Greek and Roman writers to confuse the constellation with Centaurus.

Sagittarius

Scorpius: The ScorpionAs mentioned regarding Orion, Gaia may have sent the scorpion to kill the mighty hunter, as he had vowed to rid the earth of all wild animals. Or Apollo might have told Gaia of Orion's boast, fearful that Orion had designs on Apollo's sister Artemis. In any case it was Gaia who sent the scorpion to kill Orion. Later the animal would chase Orion across the heavens, but it could never catch him, for the scorpion was so placed that it would rise in the east only after Orion had safely disappeared over the western horizon.

Scorpius

Taurus: The Bull

Is Taurus attacking Orion, the Hunter, or are the Horns of the Bull the real story? The horn was a symbol of fertility and bountiful riches in many cultures for thousands of years, and it is probably the case here, for the constellation would have announced the Vernal Equinox at around 4000 BC.

Taurus

Virgo: The VirginVirgo is the second largest constellation (after Hydra). As a member of the Zodiac, Virgo has a number of ancient myths and tales. The Sun passes through Virgo in mid-September, and is therefore the constellation that announces the harvest. Virgo is often represented as a "maiden" (as its name indicates). In antiquity, she may have been Isis, the Egyptian protectress of the living and the dead and the principal mother goddess.

Virgo