ASTR 101 Chapter Notes - Chapter 4: Equinox, Celestial Equator, Right Ascension
Document Summary
4. 1: earth and sky: how are latitude and longitude used on a map, use longitude and latitude to find cities on a globe. E(cid:567)uino(cid:628): a point in the sk(cid:629) (cid:623)he(cid:568)e the e(cid:428)lipti(cid:428) (cid:1634)sun"s path(cid:1635) (cid:428)(cid:568)osses the celestial equator: right ascension can be expressed in either units of angles or in units of time. 360 degrees = 24 hours; 15 degrees = 1 hour. 4. 3: keeping time: difference between solar day and sidereal day, solar day: rotation period of earth with respect to the sun, sidereal day: defined in terms the rotation period of earth with respect of the stars. If strictly observed people on airplanes would have to change their clocks every minute. Thus, time zones are created so that people only reset their watch after a full hour: international date line: at the date line, the date of calendar is changed on day to compensate for the time changes.