Constellations pg. 617-620. 1. # of stars? 2. Maps of sky Declination Right Ascension Earth’s spin 3. Constellations Define Names of key ones Asterisms. There are about 6000 named, visible stars in the sky. Astronomy: the oldest science !. Aristotelian view Has the earth and
1. # of stars?
2. Maps of sky
Names of key ones
There are about 6000 named, visible stars in the sky.
Has the earth and
sky on fixed spheres
An imaginary bubble that surrounds Earth onto which all the stars are positioned.
Like Earth, the Celestial sphere has a “North Pole”, a “South Pole”, and an equator.
Shuffle the deck and have sum fun
Stars, constellations, planets, can be found using the coordinates of declination and right ascension on the celestial sphere.
Locate Cygnus the Swan (looks like a cross)
DEC is measured from the celestial equator in degrees (similar to __________).
Measurement to the
NORTH is positive. The celestial North Pole is at +90 degrees DEC.
Measurement to the
South is negative.
The South Celestial Pole is
at _______degrees DEC
RA(right ascension) is similar to _______ is measured in hours, minutes, and seconds, as if we were measuring time instead of position!
RA reads to the EAST.
Astronomers decided to begin RA at the point where the path of the ecliptic crosses the celestial equator: the first day of SPRING.
We see a “flat” image of the stars in the constellations, but the stars are actually located at varying distances from earth.
It is actually Earth that is at an angle (tipped over at an angle of 23.5°
Ecliptic: the path of the sunthrough the sky
Has Polaris always been our North Star?
The 12 constellations that move through during the year.
Do you see a pattern in these stars?
The Northern Crown
Draco the Dragon
The last star in the handle of the Little Dipper is the North Star: Polaris: The North Star
Can you find the stars of the Big Dipper in the constellation?
the larger constellation
The “tea pot” asterism in the constellation Sagittarius