Altitude AzimuthAltitude Azimuth33rdrd Coordinate System Coordinate System Your zenithYour zenith 180 degrees from you zenith is Nadir 180 degrees from you zenith is Nadir

directly on the other side of earthdirectly on the other side of earth We can only see the things above our We can only see the things above our

horizon linehorizon line Anything below our horizon line is Anything below our horizon line is

denoted as negative altitudesdenoted as negative altitudes We need more than altitude to place a We need more than altitude to place a

pinpoint a celestial body in our skypinpoint a celestial body in our sky We need an AzimuthWe need an Azimuth

Azimuth ZnAzimuth Zn

We measure in reference to the We measure in reference to the horizon such as 0 degrees at true horizon such as 0 degrees at true northnorth

Runs clockwise up to 360 degreesRuns clockwise up to 360 degrees

Altitude Azimuth Altitude Azimuth

Uses the altitude in horizontal circlesUses the altitude in horizontal circles– Principal verticle circle (due north and Principal verticle circle (due north and

south)south) Azimuth in vertical circlesAzimuth in vertical circles

– Each has an upper branch and a lower Each has an upper branch and a lower branchbranch

– Prime VerticalPrime Vertical Passes through 90 (which would be due Passes through 90 (which would be due

east) 270 (which would be due west)east) 270 (which would be due west)

Create an Azimuth Zn Create an Azimuth Zn SphereSphere 2 paper plates marked with hole 2 paper plates marked with hole

at top and bottom,at top and bottom, Cut around from hole to hole, do Cut around from hole to hole, do

not cut completely apart.not cut completely apart. Turn and glue.Turn and glue. Mark our 0N, 90E, 180S, and Mark our 0N, 90E, 180S, and

270W degrees.270W degrees.