Photographing a faint planet requires keeping its much brighter star out of the way

A planet can be present in an image and still disappear beneath the light of its host star. Roman’s coronagraph is designed to suppress that glare so much fainter companions can be studied directly.

The Max Planck contribution described here is a set of precision mechanisms that keep optical components aligned. A mask alone is not enough: small changes in the optical system can allow starlight to overwhelm the desired signal.

The immediate ambition concerns planets such as cooler gas giants. Imaging an Earth-like planet with future instruments is a longer-term goal, not a capability this article demonstrates. The engineering account makes clear why telescope progress depends on control and stability as well as collecting more light.