Lecture 1: The Sky

Question 1

Celestial Sphere

Answer 1

• Stars appear to lie on the great celestial sphere around Earth
• Appears to rotate east to west because of the rotation of the Earth

Question 2

Measuring Positions in the Sky

Answer 2

• 1 degree (º) = 60 arcmin (‘) = 3600 arcsec (‘’)
• latitude is declination for sky
• longitude is right ascension for sky (hrs, min, sec)

Question 3

Spherical Coordinate System

Answer 3

• Zenith is directly overhead (90º)
• Azimuth is at horizon (0º)