Solamagic irradiance diagram (BSD)
The SOLAMAGIC BSD is a 90° section of a polar diagrm, a two dimensional coordinate system in which the irradiance in the direction of the two main radiator axes (cross-wise and length-wise) is definded by an angle and a distance.
The BSD gives you an at-a-glance overview of the distribution of radiation over a defined area. All SOLAMAGIC BSD's are based on a distance of 1500 mm between the radiator and the area. This is typically the area in which radiated heat is required.
You can use the following formula to ascertain the distance from the middle of the radiation source in cross-wise or length-wise direction:
α stands for the angle
r stands for the height of the radiator
tan(α) * r = tan(20)*1500 mm = 546 mm