| 2.9. | "Illumination of the retro-reflecting device" is the abbreviated expression used conventionally to designate the illumination measured in a plane perpendicular to the incident rays and passing through the centre of reference. | a0c0 |
| 2.9. | "Illumination of the retro-reflecting device" is the abbreviated expression used conventionally to designate the illumination measured in a plane perpendicular to the incident rays and passing through the centre of reference. | a0c0 |