Note 1 to entry: Cylindrical irradiance is sometimes also defined as arithmetic mean of the vertical irradiance E_e,v at a point

${\displaystyle E_{\text{e}\text{,c}}=\frac{1}{2\pi }{\displaystyle \underset{0}{\overset{2\pi }{\int }}{E}_{\text{e}\text{,v}}}\text{d}\phi }$

where E_e,v is the vertical irradiance for an area element with its normal in the direction φ, and φ is the angle in the plane perpendicular to the axis of the cylinder.

Note 2 to entry: The corresponding photometric quantity is "cylindrical illuminance". The corresponding quantity for photons is "photon cylindrical irradiance".

Note 3 to entry: The cylindrical irradiance is expressed in watt per square metre (W·m⁻²).

Note 4 to entry: This entry was numbered 845-01-41 in IEC 60050-845:1987.