  A flux-calibrated high resolution spectrum of the airglow emission is a
practical lambda-calibration reference for astronomical spectral observations.
It is also useful for constraining the molecular parameters of the OH molecule
and the physical conditions in the upper mesosphere. methods: We use the data
collected during the first technical commissioning of the GIANO spectrograph at
the Telescopio Nazionale Galileo (TNG). The high resolution (R~50,000) spectrum
simultaneously covers the 0.95-2.4 micron wavelength range. Relative flux
calibration is achieved by the simultaneous observation of spectrophotometric
standard star. results: We derive a list of improved positions and intensities
of OH infrared lines. The list includes Lambda-split doublets many of which are
spectrally resolved. Compared to previous works, the new results correct errors
in the wavelengths of the Q-branch transitions. The relative fluxes of OH lines
from different vibrational bands show remarkable deviations from theoretical
predictions: the Deltav=3,4 lines are a factor of 2 and 4 brighter than
expected. We also find evidence of a significant fraction (1-4%) of OH
molecules with ``non-thermal'' population of high-J levels. Finally we list
wavelengths and fluxes of 153 lines not attributable to OH. Most of these can
be associated to O2, while 37 lines in the H band are not identified. The O2
and unidentified lines in the H band account for ~5% of the total airglow flux
in this band.
