Published online by Cambridge University Press: 28 May 2003
The general formalism for Lyot and Roddier & Roddier coronagraphy is detailed. The influence of the masksize, chromatism and central obscuration are discussed. The necessity of entrance pupil apodization forcoronagraphy is introduced from the fundamental limitation that appears in the classical technique. Prolatespheroidal functions are presented as the natural apodizations for coronagraphy.