Heliograph Solar Weather Sentry

Heliograph watches the Sun from the L1 Lagrange point, 1.5 million kilometres sunward of Earth. Its coronagraph and particle detectors spot coronal mass ejections as they leave the Sun and estimate their speed and direction, typically giving inner-system traffic between 14 and 40 hours of warning.

For a Halcyon Starliner carrying 1,200 passengers, that warning means time to move everyone into the shielded core decks. Seraph Medevac crews also rely on Heliograph advisories to decide whether a rescue can be flown safely or must wait for a storm to pass.

Warnings are broadcast free over the Lantern relays and published under CC-BY-4.0. Many partner fleets, from Earth–Luna shuttle lines to Belt freighters, integrate the shelter advisories directly into their flight-deck alerting.

The team welcomes contributions to the CME arrival-time model and to the public alert format specification. The full set of outputs (solar flare warnings, coronal mass ejection tracks and shelter advisories) is licensed CC-BY-4.0, with source and documentation at https://git.halcyon.example/heliograph. Halcyon commits to keeping it available for at least twenty years, with older versions preserved in the open data archive. Feedback from partners shapes the roadmap; most new features over the past two years began as a request on the public tracker.