diff options
| -rw-r--r-- | solar.c | 11 |
1 files changed, 6 insertions, 5 deletions
@@ -163,7 +163,7 @@ static double sun_equation_of_centre(double t) { double a = sun_geometric_mean_anomaly(t), r; - r = sin(1.0 * a) * fma(fma(-0.000014, t, 0.004817), t, 1.914602); + r = sin(1.0 * a) * fma(fma(-0.000014, t, -0.004817), t, 1.914602); r = fma(sin(2.0 * a), fma(-0.000101, t, 0.019993), r); r = fma(sin(3.0 * a), 0.000289, r); return radians(r); @@ -241,7 +241,7 @@ solar_declination(double t) * between apparent and mean solar time * * @param t The time in Julian Centuries - * @return The equation of time, in degrees + * @return The equation of time, in minutes of time */ static double equation_of_time(double t) @@ -249,13 +249,14 @@ equation_of_time(double t) double l = sun_geometric_mean_longitude(t); double e = earth_orbit_eccentricity(t); double m = sun_geometric_mean_anomaly(t); - double y = pow(tan(corrected_mean_ecliptic_obliquity(t) / 2.0), 2.0); + double y = tan(corrected_mean_ecliptic_obliquity(t) / 2.0; double r, c, s; + y *= y; s = y * sin(2.0 * l); c = y * cos(2.0 * l); r = fma(fma(4.0, c, -2.0), e * sin(m), s); - r = fma(pow(0.50 * y, 2.0), sin(-4.0 * l), r); - r = fma(pow(1.25 * e, 2.0), sin(-2.0 * m), r); + r = fma(-0.5 * y*y, sin(4.0 * l), r); + r = fma(-1.25 * e*e, sin(2.0 * m), r); return 4.0 * degrees(r); } |