The experimental study of sodium layer is relevant to fields such as adaptive optics, in particular for laser guide star generation. We have developed an instrument to make systematic measures of the most relevant parameters of the sodium layer above canarian observatories. The measurement provides information about sodium layer: the medium altitude, the columnal abundance, the density profile and temporal evolution. These observations are important to design the new generation of adaptive optic instruments. We present the experimental set-up, the first results of the experiment and the plans to conduct a statistical study in the future.