In a lithographic apparatus, a control system is provided to automatically reduce throughput in the event that lens-heating aberrations exceed a certain threshold. The determination of whether lens-heating aberrations will exceed the threshold may be based upon a prediction, e.g. using a lens-heating model, or on measurements taken from a previously exposed substrate. Reduction of throughput of the device manufacture may be effected by reducing beam power or the duty cycle of the apparatus. In a particular embodiment, the time taken for substrate movement between exposure portions is increased.