Threshold of Illuminance: Difference between revisions
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'''2-1- | '''urn:mrn:iala:dic:2-1-0390''' | ||
Alternative term: Visual Threshold | Alternative term: Visual Threshold | ||
Threshold of illuminance is the lowest level of illuminance from a point source of light, against a given background level of luminance, that causes a visual response at the eye. | |||
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[[Category:Alphabetical Index]] | [[Category:Alphabetical Index]] | ||
[[Category:IALA Dictionary 1970-89 Edition]] | [[Category:IALA Dictionary 1970-89 Edition]] | ||
[[Category:IALA Dictionary 2023 Revision]] | |||
Latest revision as of 12:53, 17 September 2026
Alternative term: Visual Threshold
Threshold of illuminance is the lowest level of illuminance from a point source of light, against a given background level of luminance, that causes a visual response at the eye.
(Originate: NAVGUIDE 2023)
Note: The internationally accepted value of the threshold of illuminance for observation of a light at night under typical maritime conditions is 2.10-7 lux (0.686 sea-mile candela, 2-1-060). This figure was agreed at the International Technical Conference of Lighthouse Authorities, Paris 1933. In Britain and U.S.A. this value is sometimes approximated by 0.67 sea-mile candela.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
