Methodology
We'd rather show our work than a mysterious number. Here's exactly how Aurorix turns raw feeds into a status and a verdict — including where our approximations can be wrong.
Status states
- QUIET — no storm watch, calm solar wind, low Kp.
- WATCH — NOAA has an active G-storm watch (from the alerts feed).
- PRIMED — the L1 solar wind is storm-favourable now: sustained southward Bz (≤ −8 nT for ≥ 20 min) with elevated speed (≥ 450 km/s), or strongly southward Bz alone (≤ −15 nT). We compute the propagation ETA and show your lead time.
- ACTIVE — a storm looks underway: estimated Kp ≥ 5, or northern hemispheric power above ~60 GW.
Precedence is ACTIVE > PRIMED > WATCH > QUIET, and a watch badge persists alongside a higher state. Every state renders a one-sentence plain-language reason, and all of it is advisory framing — never a guarantee.
Propagation ETA
When PRIMED, we estimate how long the enhanced solar wind takes to reach Earth: minutes ≈ distance ÷ speed. We use the active spacecraft's live sunward distance from the ephemeris feed when available (about 1.5 million km at L1), otherwise that nominal distance. At 700 km/s that's ≈ 36 minutes; at 450 km/s ≈ 56 minutes.
Geomagnetic latitude (±1–2°)
Aurora is organised around the geomagnetic pole, not the geographic one, which is why the northern US sees aurora more readily than its map latitude suggests. We convert your location to geomagnetic latitude with a centered-dipole approximation (pole at ~80.7°N, 72.7°W, IGRF ~2025). Expect ±1–2° of error versus full corrected-geomagnetic coordinates — occasionally up to ~3°. A future refinement is the eccentric dipole or a bundled AACGM grid.
Required Kp for your latitude
We map Kp to the geomagnetic latitude of the auroral oval's equatorward edge (roughly where aurora is overhead), using the widely-published ~2°-per-Kp relation, and offset it by ~6° equatorward for horizon visibility (tall rays and red emission are seen from further away). We always show both thresholds and label the overhead-vs-horizon distinction.
Darkness gate
We treat the sky as dark enough when the sun's geometric centre is below −12° (nautical twilight) at your location and time, computed client-side with the Astronomy Engine. That avoids over-gating high-latitude summers where it never gets fully dark. The moon is an interference note (flagged above 50% illumination when it's up), never a hard gate.
Honesty covenant
Every displayed value carries a machine "data as of" stamp. If a feed is delayed, we show a stamped last-known-good value and say so — we never invent numbers or hide staleness. See our sources.