CATEcor: an Open Science, Shaded-Truss, Externally-Occulted Coronagraph

TL;DR

CATEcor is a portable, cost-effective coronagraph utilizing a novel shaded truss external occultation design, aimed at accessible solar corona observation during eclipses or for educational purposes, with potential for broader scientific applications.

Contribution

The paper introduces the CATEcor coronagraph design, demonstrating a simple, open-science approach using 3D-printed parts and a shaded truss occultation, suitable for amateur and educational use.

Findings

Successfully observes solar corona during eclipses

Low-cost, easily replicable design using 3D printing

Potential for broader scientific and educational applications

Abstract

We present the design of a portable coronagraph, CATEcor, that incorporates a novel "shaded truss" style of external occultation and serves as a proof-of-concept for that family of coronagraphs. The shaded truss design style has the potential for broad application in various scientific settings. We conceived CATEcor itself as a simple instrument to observe the corona during the darker skies available during a partial solar eclipse, or for students or interested amateurs to detect the corona under ideal non-eclipsed conditions. CATEcor is therefore optimized for simplicity and accessibility to the public. It is implemented using an existing dioptric telescope and an adapter rig that mounts in front of the objective lens, restricting the telescope aperture and providing external occultation. The adapter rig, including occulter, is fabricated using fusion deposition modeling (FDM; colloquially "3D printing"), greatly reducing cost. The structure is designed to be integrated with moderate care and may be replicated in a university or amateur setting. While CATEcor is a simple demonstration unit, the design concept, process, and trades are useful for other more sophisticated coronagraphs in the same general family, which might operate under normal daytime skies outside the annular-eclipse conditions used for CATEcor.