  ASTRONIRCAM is a cryogenic-cooled slit spectrograph for the spectral range
1-2.5 mkm installed at the Nasmyth focus of the 2.5-meter telescope of the
Caucasian observatory of Sternberg Astronomical Institute of Lomonosov Moscow
State University. The instrument is equipped with the HAWAII-2RG 2048x2048
HgCdTe array. Grisms are used as dispersive elements. In the photometric mode
ASTRONIRCAM allows for extended astronomical object imaging in the field of
view of 4.6x4.6 arc minutes with the 0.269 arcsec/pixel scale in standard
photometric bands J, H, K and Ks as well as in narrow-band filters CH_4, [Fe
II], H_2 v=1-0 S(1), Br_gamma and CO. In the spectroscopic mode, ASTRONIRCAM
takes spectra of extended or point-like sources with spectral resolution
R=lambda/Delta lambda <= 1200. The general design, optical system, detector
electronics and readout, amplification and digitization scheme are considered.
The conversion factor GAIN measurement results are described as well as its
dependence on the accumulated signal (non-linearity). The full transmission of
the atmosphere-to-detector train ranges from 40 to 50\% in the wide-band
photometry mode. The ASTRONIRCAM sensitivity at the 2.5-m telescope is
characterized by the limiting J=20, K=19 star magnitudes measured with the 10%
precision and 15 minutes integration at the 1 arcsec atmospheric seeing
conditions. The references to first results published on the base of
ASTRONIRCAM observations are given.
