English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Direct imaging of Earth-like exoplanets requires high contrast imagingcapability and high angular resolution. Primary mirror segmentation is a keytechnological solution for large-aperture telescopes because it opens the pathtoward significantly increasing the angular resolution. The segments are keptaligned by an active optics system that must reduce segment misalignments belowtens of nm RMS to achieve the high optical quality required for astronomicalscience programs. The development of cophasing techniques is mandatory for thenext generation of space- and ground-based segmented telescopes, which bothshare the need for increasing spatial resolution. We propose a new focal planecophasing sensor that exploits the scientific image of a coronagraphicinstrument to retrieve simultaneously piston and tip-tilt misalignments. Theself-coherent camera phasing sensor (SCC-PS) adequately combines the SCCproperties to segmented telescope architectures with adapted segmentmisalignment estimators and image processing. An overview of the systemarchitecture, and a thorough performance and sensitivity analysis, including aclosed-loop efficiency, are presented by means of numerical simulations. TheSCC-PS estimates simultaneously piston and tip-tilt misalignments and correctsthem in closed-loop operation. The SCC-PS does not require any a priori on thesignal at the segment boundaries or any dedicated optical path. It has amoderate sensitivity to misalignments, virtually none to pupil shear, and isinsensitive to segment gaps and edge effects. Primary mirror phasing can beachieved with bright natural guide star. The SCC-PS is a noninvasive conceptand an efficient phasing sensor from the image domain. It is an attractivecandidate for segment cophasing at the instrument level or alternatively at thetelescope level, as usually envisioned in current space- and ground-basedobservatories.

The self-coherent camera as a focal plane fine phasing sensor