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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 constellations are recognized. They divide the sky into disjoint units. Every star in the sky is in one of these constellations.
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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.
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.
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.
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.
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.
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 • 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
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
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
Latitude and Longitude Beavercreek, OH Latitude: 39.73 N, Longitude: 84.06 W
Different sets of constellations are visible in northern and southern skies. The Altitude of the celestial pole (Polaris) = your latitude
Counter-Clockwise Rotation Clockwise Rotation Northern Hemisphere Southern Hemisphere The Altitude of the celestial pole (Polaris) = your latitude
Right Ascension and Declination • Right Ascension (RA): Analogous to longitude, but on the celestial sphere. • It is the east-west angle between the vernal equinox and a location on the celestial sphere. • Declination (dec): Analogous to latitude, but on the celestial sphere. • It is the north-south angle between the celestial equator and a location on the celestial sphere.
Units of R.A. 360o = 24h 15o/h
