The azimuth of the sun denotes the direction of the sun with respect to the north-south direction. Similarly, the azimuth of a tilted plane, or slope or flat collector, is the orientation of this plane with respect to the north-south direction. The following rules apply for azimuth: value 0° means true south orientation for northern hemisphere sites and inversely, true north for southern hemisphere sites. In both cases, eastern orientations are negative and western orientations are positive; -90° is true east and 90° is true west.  Accordingly, the azimuth ranges from -180° to +180°.

Tilt is the inclination angle of a tilted plane, or slope or flat collector, over the horizontal plane. It is 0° for horizontal planes and reaches 90° for vertical planes.

All angles are given in degrees (decimal) as a standard.