The investigators will study the density and temperature structure of the middle atmosphere using a Rayleigh lidar facility using the Firepond Telescope in Massachusetts. The lidar will be moved from its current location in Logan, Utah, and will be deployed and operated at its new site near the Millstone Hill incoherent scatter radar facility. The coordinated observations with the radar and nearby optical instruments will allow studies of the dynamics of the middle atmosphere, including gravity waves, neutral winds, and mesospheric inversion layers.