Allectra has recently supplied some custom manufactured vacuum components for the Giano-B Spectrograph at the Italian Galileo Telescope TNG in the Canary Islands. The vessels (for which we supplied custom tubes, valves and various accessories) for gas-cell absorption will be mounted in the pre-slit of the near-infrared spectrograph.
GIANO-B is a high-resolution (R = 50, 000) near-infrared (NIR) echelle spectrograph working in the 0.95 to 2.45 micron range. It is used for several purposes. One of them is the search of extrasolar planets with the high precision radial velocities method.
The aim of gas-cell is thus to imprint molecular features on the star spectrum itself, to have an inertial reference frame. In this way (the gas-cell is illuminated by the target), wavelength calibration exposures can be recorded simultaneously.
The gas-cell wavelength calibration method is the only technique that provides wavelength reference information and enables monitoring of instrumental effects such as drifts in the dispersion relation and changes in slit illumination simultaneously with the astronomical observation, both in time and co-located on the detector. With this technique, a precision of about 3 m/s in the radial velocity can be achieved.
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