AY 101 Lecture Notes - Lecture 2: Celestial Equator, Northern Hemisphere, Lunar Phase

• School: University of Alabama
• Department: Astronomy
• Course: AY 101
• Professor: James Irwin

Document Summary

What can we see in the night sky: with the naked eye, we can see more than 2000 stars as well as the milky way, the. Large and small magellanic clouds, and the andromeda galaxy (barely) The milky way: a band of light making a circle around the celestial sphere. It"s ou(cid:396) (cid:448)ie(cid:449) i(cid:374)to the pla(cid:374)e of ou(cid:396) gala(cid:454)(cid:455) Constellations: a constellation is a region of the sky it has no real astronomical significance, eight-right constellations fill the entire (north and south) sky, many southern sky constellations have lame names. We measure the sky using angles: the sun and full moon are degrees wide, 1 circle=360 degrees, 1 degree=60 arcminutes, 1 arcminute=60 arcseconds. Why do stars (or sun) rise and set: earth rotates from west to east, so stars (and sun, moon, planets) appear to circle from east (rise) to west (set) in a given day.