Initial commit

1 files changed, 251 insertions, 0 deletions

diff --git a/math/slalib/plante.f b/math/slalib/plante.f
new file mode 100644
index 00000000..585e764d
--- /dev/null
+++ b/math/slalib/plante.f
@@ -0,0 +1,251 @@
+      SUBROUTINE slPLTE (DATE, ELONG, PHI, JFORM, EPOCH,
+     :                       ORBINC, ANODE, PERIH, AORQ, E,
+     :                       AORL, DM, RA, DEC, R, JSTAT)
+*+
+*     - - - - - - -
+*      P L T E
+*     - - - - - - -
+*
+*  Topocentric apparent RA,Dec of a Solar-System object whose
+*  heliocentric orbital elements are known.
+*
+*  Given:
+*     DATE     d     MJD of observation (JD - 2400000.5, Notes 1,5)
+*     ELONG    d     observer's east longitude (radians, Note 2)
+*     PHI      d     observer's geodetic latitude (radians, Note 2)
+*     JFORM    i     choice of element set (1-3; Notes 3-6)
+*     EPOCH    d     epoch of elements (TT MJD, Note 5)
+*     ORBINC   d     inclination (radians)
+*     ANODE    d     longitude of the ascending node (radians)
+*     PERIH    d     longitude or argument of perihelion (radians)
+*     AORQ     d     mean distance or perihelion distance (AU)
+*     E        d     eccentricity
+*     AORL     d     mean anomaly or longitude (radians, JFORM=1,2 only)
+*     DM       d     daily motion (radians, JFORM=1 only )
+*
+*  Returned:
+*     RA,DEC   d     RA, Dec (topocentric apparent, radians)
+*     R        d     distance from observer (AU)
+*     JSTAT    i     status:  0 = OK
+*                            -1 = illegal JFORM
+*                            -2 = illegal E
+*                            -3 = illegal AORQ
+*                            -4 = illegal DM
+*                            -5 = numerical error
+*
+*  Called: slELUE, slPLTU
+*
+*  Notes:
+*
+*  1  DATE is the instant for which the prediction is required.  It is
+*     in the TT timescale (formerly Ephemeris Time, ET) and is a
+*     Modified Julian Date (JD-2400000.5).
+*
+*  2  The longitude and latitude allow correction for geocentric
+*     parallax.  This is usually a small effect, but can become
+*     important for near-Earth asteroids.  Geocentric positions can be
+*     generated by appropriate use of routines slEVP (or slEPV) and
+*     slPLNE.
+*
+*  3  The elements are with respect to the J2000 ecliptic and equinox.
+*
+*  4  A choice of three different element-set options is available:
+*
+*     Option JFORM = 1, suitable for the major planets:
+*
+*       EPOCH  = epoch of elements (TT MJD)
+*       ORBINC = inclination i (radians)
+*       ANODE  = longitude of the ascending node, big omega (radians)
+*       PERIH  = longitude of perihelion, curly pi (radians)
+*       AORQ   = mean distance, a (AU)
+*       E      = eccentricity, e (range 0 to <1)
+*       AORL   = mean longitude L (radians)
+*       DM     = daily motion (radians)
+*
+*     Option JFORM = 2, suitable for minor planets:
+*
+*       EPOCH  = epoch of elements (TT MJD)
+*       ORBINC = inclination i (radians)
+*       ANODE  = longitude of the ascending node, big omega (radians)
+*       PERIH  = argument of perihelion, little omega (radians)
+*       AORQ   = mean distance, a (AU)
+*       E      = eccentricity, e (range 0 to <1)
+*       AORL   = mean anomaly M (radians)
+*
+*     Option JFORM = 3, suitable for comets:
+*
+*       EPOCH  = epoch of elements and perihelion (TT MJD)
+*       ORBINC = inclination i (radians)
+*       ANODE  = longitude of the ascending node, big omega (radians)
+*       PERIH  = argument of perihelion, little omega (radians)
+*       AORQ   = perihelion distance, q (AU)
+*       E      = eccentricity, e (range 0 to 10)
+*
+*     Unused arguments (DM for JFORM=2, AORL and DM for JFORM=3) are not
+*     accessed.
+*
+*  5  Each of the three element sets defines an unperturbed heliocentric
+*     orbit.  For a given epoch of observation, the position of the body
+*     in its orbit can be predicted from these elements, which are
+*     called "osculating elements", using standard two-body analytical
+*     solutions.  However, due to planetary perturbations, a given set
+*     of osculating elements remains usable for only as long as the
+*     unperturbed orbit that it describes is an adequate approximation
+*     to reality.  Attached to such a set of elements is a date called
+*     the "osculating epoch", at which the elements are, momentarily,
+*     a perfect representation of the instantaneous position and
+*     velocity of the body.
+*
+*     Therefore, for any given problem there are up to three different
+*     epochs in play, and it is vital to distinguish clearly between
+*     them:
+*
+*     . The epoch of observation:  the moment in time for which the
+*       position of the body is to be predicted.
+*
+*     . The epoch defining the position of the body:  the moment in time
+*       at which, in the absence of purturbations, the specified
+*       position (mean longitude, mean anomaly, or perihelion) is
+*       reached.
+*
+*     . The osculating epoch:  the moment in time at which the given
+*       elements are correct.
+*
+*     For the major-planet and minor-planet cases it is usual to make
+*     the epoch that defines the position of the body the same as the
+*     epoch of osculation.  Thus, only two different epochs are
+*     involved:  the epoch of the elements and the epoch of observation.
+*
+*     For comets, the epoch of perihelion fixes the position in the
+*     orbit and in general a different epoch of osculation will be
+*     chosen.  Thus, all three types of epoch are involved.
+*
+*     For the present routine:
+*
+*     . The epoch of observation is the argument DATE.
+*
+*     . The epoch defining the position of the body is the argument
+*       EPOCH.
+*
+*     . The osculating epoch is not used and is assumed to be close
+*       enough to the epoch of observation to deliver adequate accuracy.
+*       If not, a preliminary call to slPRTL may be used to update
+*       the element-set (and its associated osculating epoch) by
+*       applying planetary perturbations.
+*
+*  6  Two important sources for orbital elements are Horizons, operated
+*     by the Jet Propulsion Laboratory, Pasadena, and the Minor Planet
+*     Center, operated by the Center for Astrophysics, Harvard.
+*
+*     The JPL Horizons elements (heliocentric, J2000 ecliptic and
+*     equinox) correspond to SLALIB arguments as follows.
+*
+*       Major planets:
+*
+*         JFORM  = 1
+*         EPOCH  = JDCT-2400000.5D0
+*         ORBINC = IN (in radians)
+*         ANODE  = OM (in radians)
+*         PERIH  = OM+W (in radians)
+*         AORQ   = A
+*         E      = EC
+*         AORL   = MA+OM+W (in radians)
+*         DM     = N (in radians)
+*
+*         Epoch of osculation = JDCT-2400000.5D0
+*
+*       Minor planets:
+*
+*         JFORM  = 2
+*         EPOCH  = JDCT-2400000.5D0
+*         ORBINC = IN (in radians)
+*         ANODE  = OM (in radians)
+*         PERIH  = W (in radians)
+*         AORQ   = A
+*         E      = EC
+*         AORL   = MA (in radians)
+*
+*         Epoch of osculation = JDCT-2400000.5D0
+*
+*       Comets:
+*
+*         JFORM  = 3
+*         EPOCH  = Tp-2400000.5D0
+*         ORBINC = IN (in radians)
+*         ANODE  = OM (in radians)
+*         PERIH  = W (in radians)
+*         AORQ   = QR
+*         E      = EC
+*
+*         Epoch of osculation = JDCT-2400000.5D0
+*
+*     The MPC elements correspond to SLALIB arguments as follows.
+*
+*       Minor planets:
+*
+*         JFORM  = 2
+*         EPOCH  = Epoch-2400000.5D0
+*         ORBINC = Incl. (in radians)
+*         ANODE  = Node (in radians)
+*         PERIH  = Perih. (in radians)
+*         AORQ   = a
+*         E      = e
+*         AORL   = M (in radians)
+*
+*         Epoch of osculation = Epoch-2400000.5D0
+*
+*       Comets:
+*
+*         JFORM  = 3
+*         EPOCH  = T-2400000.5D0
+*         ORBINC = Incl. (in radians)
+*         ANODE  = Node. (in radians)
+*         PERIH  = Perih. (in radians)
+*         AORQ   = q
+*         E      = e
+*
+*         Epoch of osculation = Epoch-2400000.5D0
+*
+*  This revision:  19 June 2004
+*
+*  Copyright (C) 2004 P.T.Wallace.  All rights reserved.
+*
+*  License:
+*    This program is free software; you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation; either version 2 of the License, or
+*    (at your option) any later version.
+*
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU General Public License for more details.
+*
+*    You should have received a copy of the GNU General Public License
+*    along with this program (see SLA_CONDITIONS); if not, write to the
+*    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+*    Boston, MA  02110-1301  USA
+*
+*  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
+*-
+
+      IMPLICIT NONE
+
+      DOUBLE PRECISION DATE,ELONG,PHI
+      INTEGER JFORM
+      DOUBLE PRECISION EPOCH,ORBINC,ANODE,PERIH,AORQ,E,
+     :                 AORL,DM,RA,DEC,R
+      INTEGER JSTAT
+
+      DOUBLE PRECISION U(13)
+
+
+*  Transform conventional elements to universal elements.
+      CALL slELUE(DATE,
+     :               JFORM,EPOCH,ORBINC,ANODE,PERIH,AORQ,E,AORL,DM,
+     :               U,JSTAT)
+
+*  If successful, make the prediction.
+      IF (JSTAT.EQ.0) CALL slPLTU(DATE,ELONG,PHI,U,RA,DEC,R,JSTAT)
+
+      END