Simplify the following text for a Grade 13 native English-speaking person.
Original: Arrhenius used the infrared observations of the moon by Frank Washington Very and Samuel Pierpont Langley at the Allegheny Observatory in Pittsburgh to calculate the absorption of infrared radiation by atmospheric CO2 and water vapor .
Simplified: Arrhenius used infrared observations of the moon to calculate the absorption of infrared radiation by atmospheric CO2 and water vapor .