first photometric axis of a luminaire when measured in the C,γ - coordinate system . Metroloogia terminibaas. Estonian Language Institute, Sõnaveeb 2026. https://sonaveeb.ee/search/unif//mea/first%20photometric%20axis%20of%20a%20luminaire%20when%20measured%20in%20the%20C%2C%CE%B3%20-%20coordinate%20system/1/eng (23.08.2026)