Astronomy / Earth
A year written by the Sun
Trace the Sun at the same mean solar time throughout a year. Remove tilt or eccentricity to discover the two sources of the figure eight.
The model and its limits
Geocentric two-body solar coordinates; equation of time from right ascension. Refraction, precession and the observer’s horizon are omitted.
Equations used in the module
Equations α = atan2(cos ε sin λ, cos λ); δ = asin(sin ε sin λ); EOT = wrap(L - α) × 720/π min
