Threshold illuminance: Difference between revisions
From Glossary of Meteorology
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|Display title=threshold illuminance | |||
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|Meaning=For a point [[light]] source at night, the smallest [[illuminance]] ''E''<sub>''thresh''</sub> at the observer that can be seen for a given surrounding [[luminance]] and state of [[dark adaptation]]. | |||
|Explanation=Although the threshold illuminance is not a constant, a dark-adapted observer can usually see a nonflashing light that produces ∼1.5×10<sup>-7</sup> [[lux]] at the eye. <br/>''See also'' [[Allard's law]], [[night visual range|night visual range]]. | |||
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Latest revision as of 11:47, 28 March 2024
For a point light source at night, the smallest illuminance Ethresh at the observer that can be seen for a given surrounding luminance and state of dark adaptation.
Although the threshold illuminance is not a constant, a dark-adapted observer can usually see a nonflashing light that produces ∼1.5×10-7 lux at the eye.
See also Allard's law, night visual range.
