GMST update

feature/19
Daniel Warner 2018-08-30 18:59:43 +01:00 committed by Daniel Warner
parent 6982421275
commit 52dcd7f0f5
1 changed files with 8 additions and 8 deletions

View File

@ -605,17 +605,17 @@ public:
*/
double ToGreenwichSiderealTime() const
{
// t = Julian centuries from 2000 Jan. 1 12h UT1
const double t = (ToJulian() - 2451545.0) / 36525.0;
// julian date of previous midnight
double jd0 = floor(ToJulian() + 0.5) - 0.5;
// julian centuries since epoch
double t = (jd0 - 2451545.0) / 36525.0;
double jdf = ToJulian() - jd0;
// Rotation angle in arcseconds
double theta = 67310.54841
+ (876600.0 * 3600.0 + 8640184.812866) * t
+ 0.093104 * t * t
- 0.0000062 * t * t * t;
double gt = 24110.54841 + t * (8640184.812866 + t * (0.093104 - t * 6.2E-6));
gt += jdf * 1.00273790935 * 86400.0;
// 360.0 / 86400.0 = 1.0 / 240.0
return Util::WrapTwoPI(Util::DegreesToRadians(theta / 240.0));
return Util::WrapTwoPI(Util::DegreesToRadians(gt / 240.0));
}
/**