The unit of solar energy relating to the amount which reaches a specific area of the earth's surface.

Unit of the intensity of radiation measured per minute and equal to one calorie.

A unit of energy per unit area, equal to 1 gramcalorie/cm² and commonly employed in radiation measurement.

United States astronomer and aviation pioneer who invented the bolometer and contributed to the design of early aircraft (1834-1906)

A measure of solar radiation; equal to one calorie per square centimeter.

a unit of solar radiation equivalent to one gram calorie per square centimeter of irradiated surface.

A unit of energy per unit area commonly employed in radiation theory. Equal to one gram-calorie per square centimeter.

Named for Samuel P. Langley (1834-1906), a pioneering solar energy researcher at the Smithsonian Institution, this unit of radiant flux is one calorie per square centimeter (cal/cm2).

A unit or measure of solar radiation; 1 calorie per square meter or 3.69 Btu per square foot.

The langley (Ly) is an international unit used to measure solar radiation (or insolation). The unit was named after Samuel Pierpont Langley (1834-1906) in 1947.