Checkerboard‐Mask Coronagraphs for High‐Contrast Imaging

Rectangular-Mask Coronagraphs for High-Contrast Imaging

We present yet another new family of masks for high-contrast imaging as required for the to-be-built terrestrial planet finder space telescope. The “best” design involves a square entrance pupil having a 4-vane spider, a square image-plane mask containing a plus-sign shaped occulter to block the starlight inside 0.6λ/D, and a Lyot-plane mask consisting of a rectangular array of rectangular open...

Pushing the Envelope : Unleashing the Potential of HighContrast Imaging

Apodized phase mask coronagraphs for arbitrary apertures

Context. With a clear circular aperture, the vortex coronagraph perfectly cancels an on-axis point source and offers a 0.9 or 1.75λ/D inner working angle for topological charge 2 or 4, respectively. Current and near-future large telescopes are on-axis, however, and the diffraction effects of the central obscuration, and the secondary supports are strong enough to prevent the detection of compan...

Comparison of coronagraphs for high contrast imaging in the context of Extremely Large Telescopes

Aims. We compare coronagraph concepts and investigate their behavior and suitability for planet finder projects with Extremely Large Telescopes (ELTs, 30-42 meters class telescopes). Methods. For this task, we analyze the impact of major error sources that occur in a coronagraphic telescope (central obscuration, secondary support, low-order segment aberrations, segment reflectivity variations, ...

Spiders in Lyot Coronagraphs

In principle, suppression of on-axis stellar light by a coronagraph is easier on an unobscured aperture telescope than on one with an obscured aperture. Recent designs such as the apodized pupil Lyot coronagraph, the ‘band-limited’ Lyot coronagraph, and several variants of phase mask coronagraphs work best on unobscured circular aperture telescopes. These designs are developed to enable the dis...