Ch 2 Observing the Sky

Geocentric

Earth at the center of the universe

Celestial sphere

circle around Earth that is our night sky

Zenith

Right over your head, 90 degrees N

Horizon

Where the sky meets the ground, 360 degrees around you

Celestial equator

90 degrees from the celestial poles, projection of the Earth's equator

Celestial poles

Projection of Earth's poles, in the same place

North circumpolar zone

stars within 38 degrees of the N celestial pole, part of the sky that never sets if your in the N hemisphere

South circumpolar zone

stars within 38 degrees of the S celestial pole, part of the sky that never rises if your in the N hemisphere

Polaris

Star that is closest to the north celestial pole, North Star

Ecliptic

the path the sun appears to take around the celestial sphere

Sun rises about __ min later each day

4

The ecliptic (does/doesn't) lie along the celestial equator

doesn't

Fixed stars

the stars that seem to maintain a fixed pattern in the sky

Wandering stars

the planets and moon that seem to move across the sky

Speed = ____ ÷ ____

distance ÷ time

Zodiac

18 degree belt that the individual paths of the moon & planets all fall within, close to the ecliptic

Constellations

88 sectors that we've divided the sky into

Asterism

indicator of especially noticeable star pattern within a constellation