diff options
author | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-03-04 21:21:30 -0500 |
---|---|---|
committer | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-03-04 21:21:30 -0500 |
commit | d54fe7c1f704a63824c5bfa0ece65245572e9b27 (patch) | |
tree | afc52015ffc2c74e0266653eecef1c8ef8ba5d91 /src/slalib/prebn.f | |
download | calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz |
Initial commit
Diffstat (limited to 'src/slalib/prebn.f')
-rw-r--r-- | src/slalib/prebn.f | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/slalib/prebn.f b/src/slalib/prebn.f new file mode 100644 index 0000000..a99dd51 --- /dev/null +++ b/src/slalib/prebn.f @@ -0,0 +1,62 @@ + SUBROUTINE sla_PREBN (BEP0, BEP1, RMATP) +*+ +* - - - - - - +* P R E B N +* - - - - - - +* +* Generate the matrix of precession between two epochs, +* using the old, pre-IAU1976, Bessel-Newcomb model, using +* Kinoshita's formulation (double precision) +* +* Given: +* BEP0 dp beginning Besselian epoch +* BEP1 dp ending Besselian epoch +* +* Returned: +* RMATP dp(3,3) precession matrix +* +* The matrix is in the sense V(BEP1) = RMATP * V(BEP0) +* +* Reference: +* Kinoshita, H. (1975) 'Formulas for precession', SAO Special +* Report No. 364, Smithsonian Institution Astrophysical +* Observatory, Cambridge, Massachusetts. +* +* Called: sla_DEULER +* +* P.T.Wallace Starlink 23 August 1996 +* +* Copyright (C) 1996 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + DOUBLE PRECISION BEP0,BEP1,RMATP(3,3) + +* Arc seconds to radians + DOUBLE PRECISION AS2R + PARAMETER (AS2R=0.484813681109535994D-5) + + DOUBLE PRECISION BIGT,T,TAS2R,W,ZETA,Z,THETA + + + +* Interval between basic epoch B1850.0 and beginning epoch in TC + BIGT = (BEP0-1850D0)/100D0 + +* Interval over which precession required, in tropical centuries + T = (BEP1-BEP0)/100D0 + +* Euler angles + TAS2R = T*AS2R + W = 2303.5548D0+(1.39720D0+0.000059D0*BIGT)*BIGT + + ZETA = (W+(0.30242D0-0.000269D0*BIGT+0.017996D0*T)*T)*TAS2R + Z = (W+(1.09478D0+0.000387D0*BIGT+0.018324D0*T)*T)*TAS2R + THETA = (2005.1125D0+(-0.85294D0-0.000365D0*BIGT)*BIGT+ + : (-0.42647D0-0.000365D0*BIGT-0.041802D0*T)*T)*TAS2R + +* Rotation matrix + CALL sla_DEULER('ZYZ',-ZETA,THETA,-Z,RMATP) + + END |