  A near-IR high-resolution, R=80000 spectrometer has been developed at IPAG to
directly characterize the atmosphere of exoplanets using adaptive optics (AO)
assisted telescopes, and a single-mode fiber-injection unit. A first technical
test with the 200' Hale telescope at Palomar Observatory occurred in March 2022
using the PALM3000 AO system offered by this telescope. Observations have also
been made at the same time with the PARVI spectrometer so that a direct
comparison can be made between the two instruments. This spectrometer uses a
virtually imaged phased array (VIPA) instead of an echelle grating, resulting
in a very compact optical layout that fits in a 0.25m3 cryostat. Using a
quarter of an H2RG detector, the spectrometer analyses the middle part of the
H-band, from 1.57 to 1.7 microns for 2 sources whose light is transferred from
the telescope to the spectrometer using single-mode fibers. By design, the
transmission of the spectrometer is expected to be 40-50%, which is 2-3 times
higher than the transmission of current high-resolution spectrometers such as
CRIRES+ and NIRSPEC. A damaged cross-disperser limited it to 21%, however. A
replacement grating with a correct, twice as high efficiency has been procured
after the on-sky demonstration. In addition to recalling the main
specifications of the VIPA spectrometer, this paper presents the control
software, the calibration process, and the reduction pipeline that have been
developed for the instrument. It also presents the results of the on-sky
technical test with the Hale telescope, as well as measurements of the
effective resolution and transmission, along with a comparison of a spectrum of
the sun obtained with the spectrometer with the BASS2000 reference spectrum.
Planned modifications are also discussed. That includes the integration of a
new dedicated H2RG detector, and of K-band optics.
