A lithographic apparatus includes a substrate table capable of holding a substrate, a projection system that projects a patterned beam of radiation onto the substrate held by the substrate table, and a sensor table that is not capable of holding a substrate but that includes a sensor capable of sensing a property of the patterned beam of radiation. In addition, a first positioning system is connected to the substrate table and displaces the substrate table into and out of a path of the patterned beam of radiation, and a second positioning system is capable of positioning the sensor table into the path of the patterned beam of radiation when the substrate table is displaced out of the path of the patterned beam of radiation.