[avr-libc-commit] [2342] Gathered some constant terms from equation_of_time. c and solar_declination.c, into ephemera_common.h

[Mike Rice]

Revision: 2342
          http://svn.sv.gnu.org/viewvc/?view=rev&root=avr-libc&revision=2342
Author:   swfltek
Date:     2013-04-09 20:04:59 +0000 (Tue, 09 Apr 2013)
Log Message:
-----------
Gathered some constant terms from equation_of_time.c and solar_declination.c,  
into ephemera_common.h

Modified Paths:
--------------
    trunk/avr-libc/libc/time/ephemera_common.h
    trunk/avr-libc/libc/time/equation_of_time.c
    trunk/avr-libc/libc/time/solar_declination.c

Modified: trunk/avr-libc/libc/time/ephemera_common.h
===================================================================
--- trunk/avr-libc/libc/time/ephemera_common.h  2013-04-08 20:24:58 UTC (rev 
2341)
+++ trunk/avr-libc/libc/time/ephemera_common.h  2013-04-09 20:04:59 UTC (rev 
2342)
@@ -37,5 +37,7 @@
 #define PERIHELION 31316400    /* perihelion of 1999, 03 jan 13:00 UTC */
 #define SOLSTICE 836160        /* winter solstice of 1999, 22 Dec 07:44 UTC */
 #define TWO_PI 6.283185307179586
+#define TROP_CYCLE 5022440.6025
+#define ANOM_CYCLE 5022680.6082
 
 #endif

Modified: trunk/avr-libc/libc/time/equation_of_time.c
===================================================================
--- trunk/avr-libc/libc/time/equation_of_time.c 2013-04-08 20:24:58 UTC (rev 
2341)
+++ trunk/avr-libc/libc/time/equation_of_time.c 2013-04-09 20:04:59 UTC (rev 
2342)
@@ -47,14 +47,13 @@
     p = *timer % ANOM_YEAR;
     p += PERIHELION;
     pf = p;
-    pf /= ANOM_YEAR;
-    pf *= TWO_PI;       /* anomalous orbital angle */
+    pf /= ANOM_CYCLE;
 
     s = *timer % TROP_YEAR;
     s += SOLSTICE;
     sf = s;
-    sf /= TROP_YEAR;
-    sf *= 2.0 * TWO_PI;     /* 2x tropical angle */
+    sf /= TROP_CYCLE;
+    sf *= 2.0;        /* 2x tropical angle */
 
     pf = sin(pf);
     sf = sin(sf);

Modified: trunk/avr-libc/libc/time/solar_declination.c
===================================================================
--- trunk/avr-libc/libc/time/solar_declination.c        2013-04-08 20:24:58 UTC 
(rev 2341)
+++ trunk/avr-libc/libc/time/solar_declination.c        2013-04-09 20:04:59 UTC 
(rev 2342)
@@ -50,15 +50,13 @@
     fT += SOLSTICE;
     fT += LAG;
     dT = fT;
-    dT /= TROP_YEAR;
-    dT *= TWO_PI;
+    dT /= TROP_CYCLE;
 
-    /* Determine approximate orbital angle relative to perihelion */
+    /* Determine approximate orbital angle, relative to perihelion */
     oV = *timer % ANOM_YEAR;
     oV += PERIHELION;
     dV = oV;
-    dV /= ANOM_YEAR;
-    dV *= TWO_PI;
+    dV /= ANOM_CYCLE;
 
     /* Derive a velocity correction factor from the perihelion angle */
     dV = sin(dV);