The commissioning of the Low-Cost NIR Extended Solar Telescope (LOCNES)

LOCNES (LO-Cost NIR Extended Solar telescope) is a solar telescope installed at the TNG (Telescopio Nazionale Galileo) in the Canary Islands. It feeds the Sun’s light into the NIR spectrograph GIANO-B through a 40-m patch of optical fibers. LOCNES has been designed to obtain high signal-to-noise ratio spectra of the Sun as a star with an accurate wavelength calibration through molecular-band cells. This is an entirely new area of investigation that will provide timely results to improve the search of telluric planets with NIR spectrographs such as iSHELL, CARMENES, NIRPS, and GIANO-B. We will extract several disc-integrated activity indicators and average magnetic field measurements for the Sun in the NIR. These parameters will then be correlated with both the RV of the Sun as a star and the resolved images of the solar disc in visible and NIR. Such an approach will allow for a better understanding of the origin of activity-induced RV variations in the two spectral domains and will help in improving the techniques for their corrections. LOCNES has been installed on the outer part of the TNG dome and it started its operation in the 2023 Springtime when we performed the commissioning of the solar telescope. The main results of the commissioning will be highlighted in this paper.