The FOC has the sharpest vision of all the science instruments. The FOC's resolution allows Hubble to single out individual stars in distant star clusters.
Resolution is the ability to distinguish two points of light as separate and distinct.
The FOC directs light down one of two optical pathways. The light enters a detector after passing through one or more filters, which permit only specific wavelengths of light to pass through. By selecting very specific wavelength ranges, scientists can look for specific features, such as the hottest stars in a particular cluster. The detector intensifies the image and then records it, much like a video camera. Images of faint objects can be built up over long exposure times.