High-contrast imager for Complex Aperture Telescopes (HiCAT): 2. Design overview and first light results

TL;DR

This paper introduces the HiCAT testbed for high-contrast imaging of complex aperture telescopes, detailing its design, alignment, and initial performance results to advance wavefront control and starlight suppression techniques.

Contribution

It presents a novel optical design approach for the HiCAT testbed, enabling studies of complex telescope geometries with first light results and alignment performance analysis.

Findings

Successful optical and optomechanical alignment achieved

Preliminary first light results demonstrate effective starlight suppression

Design approach minimizes amplitude-induced errors for high contrast

Abstract

We present a new high-contrast imaging testbed designed to provide complete solutions in wavefront sensing, control and starlight suppression with complex aperture telescopes. The testbed was designed to enable a wide range of studies of the effects of such telescope geometries, with primary mirror segmentation, central obstruction, and spiders. The associated diffraction features in the point spread function make high-contrast imaging more challenging. In particular the testbed will be compatible with both AFTA-like and ATLAST-like aperture shapes, respectively on-axis monolithic, and on-axis segmented telescopes. The testbed optical design was developed using a novel approach to define the layout and surface error requirements to minimize amplitude-induced errors at the target contrast level performance. In this communication we compare the as-built surface errors for each optic to their specifications based on end-to-end Fresnel modeling of the testbed. We also report on the testbed optical and optomechanical alignment performance, coronagraph design and manufacturing, and preliminary first light results.