(Unit: degree or radian)
a) angle of incidence
angle between the direct irradiant beam and the normal to the active surface
b) aperture angle
subtended half angle of the aperture of the cylinder in the centre of a detector
NOTE 1 A full angle is used occasionally instead of a half angle
c) azimuth angle
(Symbol: a)
projected angle between a straight line from the apparent position of the sun to the point of observation and a horizontal line normal to the equator
NOTE 2 Azimuth angle is measured from due north in the southern hemisphere and from due south in the northern hemisphere
NOTE 3 Negative azimuth values indicate an eastern orientation and positive values, a western orientation
d) solar elevation angle
(Symbol: q)
angle between the direct solar beam and the horizontal plane
e) tilt angle
angle between the horizontal plane and the plane of the PV module surface |