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Goals Connect the dots" to form constellations from stars Recognize a few famous constellations and asterisms and know the myths behind them: Ursa Major- The Big Bear Ursa Minor- The Little Bear Draco- The Dragon Cepheus- The King of Ethiopia Cassiopia - The Queen of Ethiopia
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Goals Connect the dots" to form constellations from stars Recognize a few famous constellations and asterismsand know the myths behind them: Ursa Major- The Big Bear Ursa Minor- The Little Bear Draco- The Dragon Cepheus-The King of Ethiopia Cassiopia-The Queen of Ethiopia Orion- The Hunter Big Dipper Little Dipper Recognize and Identify the brightest stars in constellations Polaris Rigel Betelgeuse Know the locations of modern and ancient pole stars Polaris Theban
As early as 5000 years ago, people began naming patterns of stars, called constellations, in the honor of mythological characters or great heroes. • Today, 88 constellationsare recognized. • They divide the sky into disjoint units. • Every star in the sky is in one of these constellations.
Astronomers label stars within a constellation based on their apparent brightness, • brightest =alpha a, • second brightest = beta b, • … • Some of the brightest stars have actual names, like Rigel & Betelgeuse (both in the constellation Orion)
Ursa Major Ursa Major, the Great Bear, is visible in the Northern Hemisphere all year long.
How to Find the Big Dipper • Depending upon the season of the year, the Big Dipper can be found high in the northern sky or low in the northern sky. • Just remember the old saying spring up and fall down. • On spring and summer evenings, the Big Dipper shine highest in the sky. On autumn and winter evenings, the Big Dipper lurks closest to the horizon. • Given an unobstructed horizon, latitudes at and north of Little Rock, Arkansas (35 degrees north) can expect to see the Big Dipper at any hour of the night for all days of the year. • As for the Little Dipper, it is circumpolar – always above the horizon – as far south as the tropic of Cancer (23.5 degrees north latitude).
Ursa Minor • Ursa Minor, the Little Bear, is visible in the Northern Hemisphere all year long. • Ursa Minor is mostly known for Polaris, the North Star, which may be found at the end of the handle.
Draco • Draco, the Dragon, used to hold special significance as the location of the pole star, but due to the Earth's precession, the pole has shifted to Polaris in Ursa Minor. • Thuban, which forms the tail was the pole star around 2600 B.C. when the ancient Egyptians were building the pyramids.
Draco • In ancient times, the Little Dipper formed the wings of the constellation Draco the Dragon. • But when the seafaring Phoenicians met with the Greek astronomer Thales around 600 B.C., they showed him how to use the Little Dipper stars to navigate. Thereby, Thales clipped Draco’s wings, to create a new constellation that gave Greek sailors a new way to steer by the stars.
Draco • Draco's stars are not very bright, but five of them have known planets. The head of the dragon consists of four stars (Beta, Gamma, Nu and Xi Draconis) in a trapezoid • From there, the dragon's body winds its way through the sky, ending between the Big Dipper and Little Dipper. From early to mid-October, shooting stars known as the Draconids appear to radiate from Draco's head.
Cepheus • The story behind it: • Cepheus was the King of Ethiopia. He married Cassiopeia and they had a daughter Andromeda. Cassiopeia was incredibly beautiful but immensely vain. She was also proud of her daughter's beauty. In fact she continually boasted that the two of them were more beautiful than any of the fifty sea nymphs who attended Poseidon's court. • These nymphs (the Nereids) complained to Poseidon, who felt he had to defend his own reputation. So he sent a flood to devastate Cepheus' kingdom. The oracles told Cepheus that in order to save his people he must sacrifice his daughter to a great sea monster: Andromeda was tied to a rock along the coastline, dressed only in her jewelry. The monster would be along in due time to take his prize. • At that moment Perseus came flying by. He had just killed the Gorgon Medusa and was carrying the severed head back to Athene. To make a long story short, he saved her then turned everyone into stone by showing them the severed head. • Poseidon then put the stone frozen Cepheus and Cassiopeia into the heavens, but with a twist: he made the vain Cassiopeia spin around on her chair, spending half the year upside down. As for Cepheus, Poseidon gave him a number of medium sized stars that go to make his square face with a pointed crown.
OrionNot a circumpolar constellation, but a seasonal constellationBetelgeuse, the right arm of Orion (or "armpit" as the name suggests), glows with a dull red. Rigel, in the opposite corner of the constellation, is blue and much brighter.
Orion is a non- circumpolar constellations Orion is only visible in the fall and winter, because in the spring and summer it would appear during the day (and so it is drowned out by the Sun).
Orion • Orion is the master of the winter skies. He lords over the heavens from late fall to early spring, with his hunting dog Sirius trailing at his feet. • The story behind it: (Orion holding an animal) • Orion was known as the "dweller of the mountain", and was famous for his prowess both as a hunter and as a lover. But when he boasted that he would eventually rid the earth of all the wild animals, his doom may have been sealed. The Earth Goddess sent the deadly scorpion to Orion to kill him. Orion engaged the scorpion in battle but quickly realized its armour was impervious to any mortal's attack. Orion then jumped into the sea and died. In his eternal hunting, Orion is careful to keep well ahead of the scorpion. Orion disappears over the horizon by the time Scorpio rises in the east, as it becomes his turn to rule the evening sky.
On the left and in the middle: Andromeda • The Andromeda constellation is famous for containing the Andromeda Nebula, the closest galaxy to our Milky Way. • On the right: The Fishes, Pisces
Betelgeuse: The Next Supernova? Betelgeuse: The Next Supernova?
Orion • On the left: The Hunter - Orion • In the middle: Name: The Bull - Taurus • On the right: Name: The Greater Dog - Canis Major
On the left: The Lion - Leo • In the middle: The Herdsman - Böötes • On the right: The Virgin - Virgo
Summer • On the left: The Crab - Cancer • In the middle: The Scorpion - Scorpio • On the right: The Archer - Sagittarius
Ecliptic Constellations & Zodiac Signs • A band of 12 constellations around the sky entered on the ecliptic (apparent path of the sun on the earth as the earth revolves around it). • Aries, Leo, Sagittarius, Taurus, Virgo, Capricorn, Gemini, Libra, Aquarius, Cancer, Scorpio, and Pisces.
Brightest Stars and Their Constellations http://www.enchantedlearning.com/subjects/astronomy/stars/bright.shtml http://www.astro.wisc.edu/~dolan/constellations/extra/brightest.html
To Polaris Angular size of moon ~ ½ o Angular distance between the “pointer stars” ~ 5o
