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| author | David A. Madore <david+git@madore.org> | 2012-04-17 19:15:56 +0200 |
|---|---|---|
| committer | David A. Madore <david+git@madore.org> | 2012-04-17 19:15:56 +0200 |
| commit | 5f00eb3230d89f98d93c6e5bc8ecfa72e4e89b07 (patch) | |
| tree | d5baba050542f345d68de244d4c8228d1781379c /org/madore/ephem/Nutation.java | |
| parent | b5dd88803374c586e165c77ac1dbf96c0d0f6ee7 (diff) | |
| download | ephem-5f00eb3230d89f98d93c6e5bc8ecfa72e4e89b07.tar.gz ephem-5f00eb3230d89f98d93c6e5bc8ecfa72e4e89b07.tar.bz2 ephem-5f00eb3230d89f98d93c6e5bc8ecfa72e4e89b07.zip | |
Use J2000 ecliptic (rather than equatorial) coordinates as starting point for precession.
We will assume that these are the coordinates returned by VSOP87.
Diffstat (limited to 'org/madore/ephem/Nutation.java')
| -rw-r--r-- | org/madore/ephem/Nutation.java | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/org/madore/ephem/Nutation.java b/org/madore/ephem/Nutation.java index bc6e721..8c37fd2 100644 --- a/org/madore/ephem/Nutation.java +++ b/org/madore/ephem/Nutation.java @@ -64,6 +64,7 @@ public final class Nutation { } public static Frames.Rotation matrix(double t) { + // Transform mean equatorial coordinates of date to true equatorial coordinates of date. Frames.Rotation mat1 = Frames.Rotation.rotx(Precession.epsilon.v(t)*Comput.arcsecond); Frames.Rotation mat2 = Frames.Rotation.rotz(-getFunc(Variable.PSI).v(t)*Comput.arcsecond).apply(mat1); Frames.Rotation mat3 = Frames.Rotation.rotx(-(Precession.epsilon.v(t)+getFunc(Variable.EPSILON).v(t))*Comput.arcsecond).apply(mat2); |