Changeset 1719 in Sophya for trunk/SophyaExt/XephemAstroLib/plans.c

Timestamp:

Oct 22, 2001, 2:08:28 PM (24 years ago)

Author:

cmv

Message:

Adapted to version 3.5 xephem cmv 22/10/2001

File:

• trunk/SophyaExt/XephemAstroLib/plans.c (modified) (4 diffs)

trunk/SophyaExt/XephemAstroLib/plans.c

@@ -108 +108 @@
  * [planet][0] = angular size at 1 AU
  * [planet][1] = magnitude at 1 AU from sun and earth and 0 deg phase angle
- */
-static double vis_elements[8][2] = {
-        /* Mercury */   { 6.74, -0.42, },
-        /* Venus */     { 16.92, -4.34, },
-        /* Mars */      { 9.36, -1.20, },
-        /* Jupiter */   { 196.74, -9.4, },
-        /* Saturn */    { 165.6, -8.88, },
-        /* Uranus */    { 65.8, -7.19, },
-        /* Neptune */   { 62.2, -6.87, },
-        /* Pluto */     { 8.2, -1.0, }
+ * [planet][2] = A
+ * [planet][3] = B
+ * [planet][4] = C
+ *   where mag correction = A*(i/100) + B*(i/100)^2 + C*(i/100)^3
+ *      i = angle between sun and earth from planet, degrees
+ * from Explanatory Supplement, 1992
+ */
+static double vis_elements[8][5] = {
+        /* Mercury */   { 6.74, -0.36, 3.8, -2.73, 2.00},
+        /* Venus */     { 16.92, -4.29, 0.09, 2.39, -.65},
+        /* Mars */      { 9.36, -1.52, 1.60, 0., 0.},
+        /* Jupiter */   { 196.74, -9.25, 0.50, 0., 0.},
+        /* Saturn */    { 165.6, -8.88, 4.40, 0., 0.},
+        /* Uranus */    { 65.8, -7.19, 0.28, 0., 0.},
+        /* Neptune */   { 62.2, -6.87, 0., 0., 0.},
+        /* Pluto */     { 8.2, -1.01, 4.1, 0., 0.}
 };
 
@@ -132 +138 @@
  *         seen from the center of the Earth for the given instant.
  *   dia:  angular diameter in arcsec at 1 AU, 
- *   mag:  visual magnitude when 1 AU from sun and earth at 0 phase angle.
+ *   mag:  visual magnitude
  *
  * all angles are in radians, all distances in AU.
@@ -148 +154 @@
 {
         static double lastmjd = -10000;
-        static double lsn, bsn, rsn;    /* geometric geocentric coords of sun */
-        static double xsn, ysn, zsn;
+        static double lsn, bsn, rsn;    /* geocentric coords of sun */
+        static double xsn, ysn, zsn;    /* cartesian " */
         double lp, bp, rp;              /* heliocentric coords of planet */
         double xp, yp, zp, rho;         /* rect. coords and geocentric dist. */
         double dt;                      /* light time */
+        double *vp;                     /* vis_elements[p] */
+        double ci, i;                   /* sun/earth angle: cos, degrees */
         int pass;
 
@@ -202 +210 @@
         }
 
-        *dia = vis_elements[p][0];
-        *mag = vis_elements[p][1];
+        vp = vis_elements[p];
+        *dia = vp[0];
+
+        /* solve plane triangle, assume sun/earth dist == 1 */
+        ci = (rp*rp + rho*rho - 1)/(2*rp*rho);
+
+        /* expl supp equation for mag */
+        if (ci < -1) ci = -1;
+        if (ci >  1) ci =  1;
+        i = raddeg(acos(ci))/100.;
+        *mag = vp[1] + 5*log10(rho*rp) + i*(vp[2] + i*(vp[3] + i*vp[4]));
+
+        /* rings contribution if SATURN */
+        if (p == SATURN) {
+            double et, st, set;
+            satrings (bp, lp, rp, lsn+PI, rsn, mjd+MJD0, &et, &st);
+            set = sin(fabs(et));
+            *mag += (-2.60 + 1.25*set)*set;
+        }
 }
 
 /* For RCS Only -- Do Not Edit */
-static char *rcsid[2] = {(char *)rcsid, "@(#) $RCSfile: plans.c,v $ $Date: 2001-04-10 14:40:47 $ $Revision: 1.1.1.1 $ $Name: not supported by cvs2svn $"};
+static char *rcsid[2] = {(char *)rcsid, "@(#) $RCSfile: plans.c,v $ $Date: 2001-10-22 12:08:27 $ $Revision: 1.2 $ $Name: not supported by cvs2svn $"};