Patent ID: 8300208

Claim:
A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a patterning device support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a: subtrate; a projection system configured to project the patterned, radiation beam onto a target portion of the substrate; an active air mount to support said projection system, the active air mount comprising at least one actuator; and a feed-forward device, the feed-forward device being configured to receive a set-point signal, the set point signal being based on a difference between a desired position of a moveable, object and an actual position of the moveable object, and. provide on the basis of the set-point signal, a feed-forward signal to the at least one actuator, wherein the feed-forward signal is designed to decrease a disturbance effect on the projection system due to movement of the movable object.