A Compact Coronagraph Design for Heliophysics Missions

A compact coronagraph design will greatly reduce the mass, volume, and cost of coronagraphs. This project will develop a compact coronagraph design for Heliophysics missions and test and evaluate the design.

Coronagraphs need to block the photospheric light of the Sun, so the corona (about a million times dimmer than the photosphere) can be imaged. Blocking the photospheric light is possible by an external occulting disk (occulter) in front of the objective lens of the solar telescope. An internal occulter, after the objective elements and other stops are positioned and sized, is used to reject light from the solar disk. One of the constant problems in coronagraphs is the photospheric light diffracted by the external occulter that enters into the coronagraph system due to scattering by the optical elements. Thus a successful rejection of the diffracted light is one of the key aspects of any coronagraph system.  By suitably designing the occulters and stops the intensity of diffracted and scattered light needs to be reduced.