Primary astronomical source
The calculation uses NASA GSFC polynomial Besselian elements for the 12 August 2026 eclipse, with VSOP87/ELP2000-85 ephemerides and ΔT = 71.4 seconds.
Local circumstances
The pipeline applies WGS84 observer coordinates and elevation, refines each contact and maximum numerically, and derives magnitude, area obscuration, totality duration, geometric solar altitude and azimuth.
City coordinates and timezones
City centroids, elevation and IANA timezone identifiers come from the GeoNames cities15000 dataset. Local time is formatted with the timezone rules available at build time.
Validation
Eight representative locations are compared against NASA, Timeanddate, Spain's Instituto Geográfico Nacional, the Iceland eclipse timetable and the Xavier Jubier path map. The build stops when explicit tolerances are exceeded.
Limitations
The results do not model terrain, buildings, vegetation, clouds or the lunar limb profile. Geometric altitude excludes atmospheric refraction, which becomes especially uncertain close to the horizon.
Verifiable sources
These sources support the data and guidance above.