thumb|Faint Object Camera (Dornier Museum)
<!--thumb|Astronauts remove the FOC to make room for the [[Advanced Camera for Surveys|ACS]]-->
thumb|Surface map of Pluto by HST/FOC
The Faint Object Camera (FOC) was a camera installed on the Hubble Space Telescope from launch in 1990 until 2002. It was replaced by the Advanced Camera for Surveys. In December 1993, Hubble's vision was corrected on STS-61 by installing COSTAR, which corrected the problem with Hubble's mirror before it reached an instrument like FOC. Later instruments had this correction built in, which is why it was possible to later remove COSTAR itself and replace it with a new science instrument.
The camera was built by Dornier GmbH and was funded by the European Space Agency. The unit actually consists of two complete and independent camera systems designed to provide extremely high resolution, exceeding 0.05 arcseconds. It is designed to view very faint UV and optical light from 115 to 650 nanometers in wavelength. FOC has been compared to a "telephoto" lens, providing a high resolution in a small field of view. FOC could distinguish between two points 0.05 arc-seconds apart.
{| class="wikitable"
!
! Angular resolution
! Field of view
|-
! Low resolution (f/48)
| 0.043 arcseconds
| 22 arcseconds
|-
! Medium resolution (f/96)
| 0.022 arcseconds
| 11 arcseconds
|-
! High resolution (f/288)
| 0.0072 arcseconds
| 3.6 arcseconds
|}
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Mira
thumb|left|400px|Hubble + FOC [[red giant star Mira A (right), officially called Omicron Ceti in the constellation Cetus, and its companion on the left. Taken on December 11, 1995]]
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Imaging examples
{|
|thumbnail|[[Pluto and its moon Charon revealed by the Hubble Faint Object Camera (1994)]]
|thumb|The "[[Einstein cross", discovered in 1985 by J. Huchra, is a large gravitational lens. 1990 Hubble image]]
|thumb|[[Nova Cygni 1992 with FOC/COSTAR]]
|}
Space work
{|
|thumb|STS-31 launches to carry Hubble into orbit, 1990
|thumb|Astronauts remove the FOC to make room for the [[Advanced Camera for Surveys|ACS instrument]]
|thumb|Columbia lands, returning FOC to Earth, 2002
|}