Ly/min
langley per minute
Intensityexact by definition
The langley per minute is one thermochemical calorie per square centimetre per minute, exactly 41840/60 or about 697.33 watts per square metre. It is the older unit of solar radiation in meteorology and agronomy, where the solar constant is about 1.95 Ly/min and daily insolation totals are reported in langleys per day. The conversion is exact, the thermochemical calorie being defined as exactly 4.184 joules.
| 1 Ly/min | 697.33333 W/m² |
Where the unit came from
Named for Samuel Pierpont Langley, who built the bolometer in 1878 and used it to measure the solar spectrum from Mount Whitney. His attempt at the solar constant was the first serious one, and the unit stayed in agricultural and climate records long after the field went metric.
Solvers that use intensity