The Faint Object Camera (FOC) was built by the European Space Agency. It is an optical and ultraviolet camera which is able to count the individual rays of light (or light particles / photons) as they arrive. The resolution of FOC is stunning - more than seven times better than Hubble's famous WFPC2 camera.

Left: The FOC - Faint Object Camera onboard Hubble. Right: An image taken with FOC. This was, at the time of observation, the first direct image of a star. The star is Betelgeuse or Alpha Orionis. It is a red supergiant star marking the left shoulder of the winter constellation Orion the Hunter. This image was only made possible because of FOC's extremely high resolution.

FOC has two complete detector systems, each producing an image on a phosphor screen that is 100 000 times brighter than the light received. A television camera then scans this phosphor image. This television camera is so sensitive that objects brighter than 21st magnitude must be dimmed by the camera's filter systems to avoid saturating the detectors.

	COSTAR - Corrective Optics Space Telescope Axial Replacement
	WFPC1 - Wide Field Planetary Camera 1