%deg here.altitude = 55; %m noonToday = datenum( '2010-07-16 12:00' ); sun_position(noonToday,here) ans = zenith: 63.368 azimuth: 84.585 Wikepedia helped get my head around what zenith and azimuth mean. Thanks to Vincent for making that so easy for me to use. His submission also has a lot of good feedback from