The Near-Infrared Spectrometer (NIRS: Noda et al. 1994,
Noda et al. 1996; see IRSA IRTS
Bibliography Listing) is a
grating spectrometer with two 12 element InSb linear
arrays, and is one of the four focal-plane instrumens
of the Infrared Telescope in Space (
IRTS) mission, which was launched in
March 1995. The NIRS was designed to measure the
absolute sky brightness with coarse spectral resolution
; searching for extragalactic background light is the
primary purpose of the obsevations. The wavelength
coverage of the NIRS ranges from 1.4 to 4.0 micron with
a spectral resolution of 0.12 micron. The field of view
is 8' x 8'. The NIRS has been calibrated and tested
with the flight IRTS telescope in the laboratory. The
response and noise were found to be as expected from
the design values. After integrating all of the
focal-plane instruments with the telescope into the
flight cryostat, NIRS shows good performance and is
able to achieve a high sensitivity in orbit.
What's the NIRS !?
