The SAGE III instrument will circle the Earth sixteen times per day. As it faces the sun during each orbit, SAGE III will measure the intensity of the Sun's light at a "Sunrise" and at a "Sunset".

At each Sunrise and Sunset the SAGE III Sun photometer system will detect and measure the intensity of sunlight striking the instrument. The aerosols and gases between the Sun and the instrument cause the Sunlight to be attenuated. Specific aerosols and gases cause a pattern of extinction of the Sun's light.

From this data, scientists will determine a species profile and Atmospheric Optical Thickness (AOT) of a vertical slice of the Earth's upper atmosphere.

At Earth's surface, the student's hand-held Sun photometer will measure the intensity of the sun's light at certain times during the day, especially during a fly-over of the SAGE III instrument.

For each time of data collection, as with the SAGE III instrument, the intensity of Sunlight striking the Sun photometer will be measured. The Sun's light will be attenuated by the aerosols and gases as it travels through the atmosphere between the Sun and the instrument. From this data, the student will determine the Atmospheric Optical Thickness (AOT) of that vertical sample of total atmosphere.

The student's surface data will be sent by Internet to be collected in a NASA database and will be used for comparison to the data collected by SAGE III and for comparison to surface data collected in various geographic regions.