An external occulter is a specially-shaped spacecraft own in formation with a telescope. It enables high-contrast imaging of the dim planetary companions of the neighboring solar system by blocking starlight before it reaches the entrance pupil. Occulters have to be designed via optimization methods that account for diffraction to most effectively block starlight. To predict occulter performance, we must verify the fidelity of the optical propagation models under scaled conditions. In this paper, we measure the contrast of a scaled occulter. The validity of the contrast calibration is determined using a baseline circular occulter. We verify contrast better than 10^-10, however the measurements do not perform as well as the prediction from theoretical modelling. We attribute this difference to glint scattering off mask edges.

Date Published: 26 September 2013
PDF: 12 pages
Proc. SPIE 8864, Techniques and Instrumentation for Detection of Exoplanets VI, 886419 (26 September 2013); doi: 10.1117/12.2024488

Published in SPIE Proceedings Vol. 8864:
Techniques and Instrumentation for Detection of Exoplanets VI
Stuart Shaklan, Editor(s)