ASTRO-110 Lecture Notes - Lecture 1: Celestial Equator, Minute And Second Of Arc
Document Summary
Declination how far/close to celestial equator/celestial poles (circles start at 0 degrees, 30, 60, 90) celestial pole. Equator is at 0 degrees declination, 90 north declination takes us to the north. Right ascension runs north/south from poles, through equator. Different system, uses hours 12 hours, 10, 8 (in hours, min, sec) labeled that way because earth is rotating and we measure that in hours, etc. Right ascension difficulty finding the origin. Poles and equator above same on earth, easier to define. Celestial meridian right ascension line at 00 hours (goes from n to s pole) 24 hours and 0 hours are at the same place the ecliptic crosses the celestial meridian at the point of 0 hours. Crosses the celestial meridian again at 12 hours. Ecliptic path the sun traces around celestial sphere as we orbit the sun. Vernal equinox equal amounts of daylight/night at crossover (spring) 0 hours. Degree (0 at equator, 90 at n, -90 at s poles)
