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The '''Near Infrared Camera and Multi-Object Spectrometer''' ('''NICMOS''') is a [[Measuring instrument|scientific instrument]] for [[infrared astronomy]], installed on the [[Hubble Space Telescope]] (HST), operating from [[1997]] to [[1999]], and from [[2002]] to the present.
NICMOS was conceived and designed by the NICMOS Instrument Definition Team centered at Steward Observatory, University of Arizona. NICMOS is aan imager and spectrometer built by [[Ball Aerospace]] that allows the HST to observe [[infrared light]], with [[wavelength]]s between 0.8 and 2.54 micrometres, providing imaging and spectroscopyslitless spectrophotometric capabilities. NICMOS contains three near-infrared detectors in three optical channels providing high (~ 0.1 arcsecond) resolution, coronagraphic and polarimetric imaging, and slitless spectroscopy in 11, 19, and 52 arcsecond square fields of view. Each optical channel contains a 256x256 pixelspixel photodiode array of [[HgCdTe|Hg<sub>0.554</sub>Cd<sub>0.446</sub>Te]] [[infrared detector]]s bonded to a sapphire substrate, read out in four independent 128x128 quadrants.
NICMOS was installed on Hubble during its second servicing mission in [[1997]], whenalong two previous [[spectrograph]] instruments were replaced bywit the [[Space Telescope Imaging Spectrograph]], replacing two earlier instruments.
When conducting infrared measurements, it is necessary to keep the infrared detectors cooled to avoid having infrared interference from the detectorinstrument's own heatthermal emissions, so the. NICMOS was designed to fit insidecontains a cryogenic [[dewar]], coolingthat thecooled detectorits detectors to ~ 61 Kelvin, and optical filters to ~ 105K, with a block of solid [[nitrogen]] ice. When NICMOS was installed in 1997, the [[dewar flask]] contained a 230 pound (104 kg) block of nitrogen ice. HoweverDue to a thermal short that arose on March 4, due1997 toduring unforseenthe designinstrument problemscommissioning, the dewar ran out of nitrogen coolant after lesssooner than twoexpected yearsin January, and had to stop operation1999. However, duringDuring Hubble Service Mission 3B in 2002, a [[cryocooler]] wasand external radiator were installed on the Hubble that providesnow additional refrigeration to thecools NICMOS through a refrigeratedcryogenic [[neon]] loop,. allowing itNICMOS was returned to resumeservice observationsoon after SM 3B, and continues in operation measurementstoday.
[[Category:Hubble Space Telescope]]
[[Category:Space science experiments]]
[[User:128.196.211.48|128.196.211.48]] 18:25, 13 December 2006 (UTC) updated: Glenn Schneider (NICMOS Project Instrument Scientist)
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