The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope (HST), operating from 1997 to 1999, and from 2002 to 2008. Images produced by NICMOS contain data from the near-infrared part of the light spectrum. NICMOS was conceived and designed by the NICMOS Instrument Definition Team centered at Steward Observatory, University of Arizona, USA. NICMOS is an imager and spectrometer built by Ball Aerospace & Technologies Corp. that allows the HST to observe infrared light, with wavelengths between 0.8 and 2.4 micrometers, providing imaging and slitless 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 256×256 pixel photodiode array of mercury cadmium telluride infrared detectors bonded to a sapphire substrate, read out in four independent 128×128 quadrants. NICMOS last worked in 2008, and has been largely replaced by the infrared channel of Wide Field Camera 3 after its installation in 2009. Limitations The infrared performance of the Hubble has limitations since it was not designed with infrared performance as an objective. For example, the mirror is kept at a stable and relatively high temperature (15 °C) by heaters. HST is a warm telescope. The IR background flux collected by cooled focal plane IR instruments like NICMOS or WFC3 is dominated, at rather short wavelengths, by telescope thermal emission rather than by zodiacal scattering. NICMOS data show that the telescope background exceeds the zodiacal background at wavelengths longer than λ ≈ 1.6μm, the exact value depending on the pointing on the sky and on the position of the Earth on its orbit. Despite this, the combination of Hubble's mirror and NICMOS offered never-before seen levels of quality in near-infrared performance at that time. Dedicated infrared telescopes like the Infrared Space Observatory were ground-breaking in their own way, but had a smaller primary mirror, and were also out of service at the time of NICMOS installation because they ran out of coolant. NICMOS later overcame this problem by using a machine chiller like a refrigerator, which allowed it operate for years until it went offline in 2008. History of NICMOS NICMOS was installed on Hubble during its second servicing mission in 1997 (STS-82) along with the Space Telescope Imaging Spectrograph, replacing two