Show pageDiscussionOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ===== Angles on the Sky ===== Primer on [[~spherical|Spherical Coordinates]]. ==== Horizontal Coordinate System ==== Discuss Altitude and Azimuth, discuss poles, fundamental plane. Discuss issues with this system for astro purposes. ==== Equatorial Coordinate System ==== Discuss degrees of arc, arc mins, arc secs. Discuss hours or arc, minutes or arc, seconds of arc. Since a complete circle contains 24h of right ascension or 360° (degrees of arc), 1/24 of a circle is measured as 1h of right ascension, or 15°; 1/1440 of a circle is measured as 1m of right ascension, or 15 minutes of arc (also written as 15′); and 1/86400 of a circle contains 1s of right ascension, or 15 seconds of arc (also written as 15″). A full circle, measured in right-ascension units, contains 24 × 60 × 60 = 86400s, or 24 × 60 = 1440m, or 24h. -- from wikipedia on RA Discuss Celestial Sphere. Discuss RA units, discuss DEC units, discuss poles, fundamental plane. Discuss Hour Angle. Discuss how to determine an object's alt/az based on RA/DEC/Time/Lat/Lon. ==== Ecliptic Coordinate System ==== Nah {{tag>[math coordinates not-done]}}