The Night Sky
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Transcript of The Night Sky
The Night Sky
Where are the stars and constellations located?
Draw the earth on it’s axis What is a sphere? What is latitude and longitude Are you good at following directions?
Warm –up
Night Sky BasicsSection 1
The stars and planets appear to be on a large sphere surrounding the earth
NOT TRUE
The celestial sphere
Aligned with earth
Celestial equator along the same line as earth equator
Celestial north pole over north pool of earth
Pittsburgh is 42 degrees lat, by 85 degrees long
Earth Coordinate System vs. The Celestial Coordinate System
Earth Coordinate System
Latitude vs. Longitude
Latitude Longitude
Measures the angle north or south of the equator
0-90 north 0- -90south
Equator is 0 degrees
Measures angle east or west
0-180 East 0-180 West
Prime Meridian is 0
Celestial Sphere Coordinate System
Declination vs. Right Ascension
Declination Right Ascension
Distance measured north/south
0-90 north 0-90 south
Latitude
Distance measured eastward on Celestial Sphere
0-24 hours
Longitude
Zenith: Point that is directly overhead
Celestial Sphere Terminology
The apparent path that the sun takes around the celestial sphere
Ecliptic
The north star Directly overhead Appears not to move
Polaris
The earth slowly wobbles on its axis of rotation.
One wobble takes approximately 26,000 years.
Because of this slow wobble, the stars SLOWLY move in a small circle in the night sky.
Precession
A star is a massive, luminous ball of plasma that is held together by gravity.
Star
Where is polaris? North pole
Equator
Pittsburgh
At zenith
At horizon
42 degrees
THERE IS NOT A SOUTH STAR!
South star
Draw a star
Draw a constellation:
Name a star:
Warm-up
A constellation is an official grouping of stars.
They are usually ancient in origin, and come
from greek mythology
Constellations
an unofficial grouping of stars that make a pattern in the sky.
will usually vary from region to region
Summer Triangle: Vega, Deneb, and Altair, Big dipper
◦ Piece of the constellations Ursa Major◦ In northern Europe, they call a part of ursa major
the “Great plow”. ◦
Asterism
visible all year round It appears to circle the celestial pole.
Circumpolar constellations
Subtract your latitude from 90 ◦ Pittsburgh: 42
◦ Florida: 30
◦ North Pole: 90
◦ Equator: 0
Finding Circumpolar constellations
1. Ursa Major, 2. Ursa Minor, 3. Cassiopea, 4. Cephius, 5. Draco.
Circumpolar constellations in our area
Constellation Names:◦ Latin names. ◦ Most of these names come from Greek
mythology.
Constellation Names and Designations
Star names◦ Arabic names. ◦ Many star names come from Mid-Eastern
mythology.
Stars in constellation are designated by their brightness.
astronomers use greek letters.
The brightest star is designated Alpha, The second brightest is designated Beta, the third brightest is designated Gamma, etc
Star Designations
Ursa Minor
Ursa Minor
Polaris (The North Star)
Ursa Major
Cassiopeia
Polaris (The North Star)
Gemini
Castor Pollux
Orion
Betelgeuse Rigel
Canis Major
Sirius
Canis Minor
Procyon
Taurus
Aldebaran Pleiades
Cygnus
Deneb
Lyra
Vega
Aquila
Altair
Ursa Major In Greek mythology, Zeus (the king of the
gods) lusts after a young woman named Callisto, a nymph of Artemis. Hera, Zeus's wife, transforms Callisto into a bear due to her jealousy of being extremely beautiful. Callisto, while in bear form later encounters her son Arcas. Arcas almost shoots the bear, but to avert the tragedy, Zeus hurls them both into the sky, forming Ursa Major.
Mythology
One story tells that Orion was killed by a giant scorpion; the gods raised him and the Scorpion to the skies,
Orion
Aquila was identified as Αετός Δίας (Aetos Dios), the eagle that carried the thunderbolts of Zeus and was sent by him to carry the shepherd boy Ganymede, whom he desired, to Mount Olympus;
Aquila