Method for reducing sidelobe impact of low order aberration in a coronagraph

The invention relates to a method for reducing a sidelobe impact of low order aberrations using a coronagraph (2) having an apodized occulting mask (10), comprising the steps of: (a) providing in the coronagraph (2) the apodized occulting disk (10) having a transmission profile which graduates from opaque to transparent along its radius and the negative of whose amplitude transmission is a Gaussian profile; (b) determining a predicted sidelobe impact of the aberrations from a particular mix of low order aberration measured in a system as described by the Zernike polynomials; (c) applying the coronagraph to a system point spread function using a given rms width for the Gaussian profile describing the apodized occulting mask (10) and determining an attenuation level of the aberration sidelobes; (d) scaling the Gaussian occulting mask (10) profile to a wider rms width if the sidelobe attenuation level is too low; and (e) repeating the steps (b) through (d) until the attenuation level is acceptable.