Stellar CCD aperture photometry is the technique of extracting information about the brightness of stars from a series of images collected over time. The light curve of a variable star can reveal useful information about the physics of the star, including a measure of its intrinsic brightness. Light curve analysis can yield information about eclipsing binary systems, and also lead to exoplanet discoveries when a planet alters the brightness of a star by crossing its disk as viewed from Earth.
In CCD photometry, we want to be able to determine a measure of the amount of radiation coming from a given star arriving on our CCD detector. Plotted as a function of time, this measurement can reveal important information about the star or star system.