From a212589865a5a59f93778e4543e7a09e39ce9107 Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Sun, 10 Jun 2001 15:12:09 +0000
Subject: [PATCH] Fixed a problem that could cause a divide by zero error
 during initialization. Contributed by Durk Talsma.

---
 simgear/ephemeris/moonpos.cxx | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/simgear/ephemeris/moonpos.cxx b/simgear/ephemeris/moonpos.cxx
index 27d62a73..47696927 100644
--- a/simgear/ephemeris/moonpos.cxx
+++ b/simgear/ephemeris/moonpos.cxx
@@ -182,7 +182,17 @@ void MoonPos::updatePosition(double mjd, double lst, double lat, Star *ourSun)
   // SG_LOG( SG_GENERAL, SG_INFO, "g = " << g );
 
   rightAscension = geoRa - mpar * rho * cos(gclat) * sin(HA) / cos (geoDec);
-  declination = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
+  if (fabs(lat) > 0) {
+      declination
+	  = geoDec - mpar * rho * sin (gclat) * sin (g - geoDec) / sin(g);
+  } else {
+      declination = geoDec;
+      // cerr << "Geocentric vs. Topocentric position" << endl;
+      // cerr << "RA (difference)  : "
+      //      << SGD_RADIANS_TO_DEGREES * (geoRa - rightAscension) << endl;
+      // cerr << "Dec (difference) : "
+      //      << SGD_RADIANS_TO_DEGREES * (geoDec - declination) << endl;
+  }
 
   /* SG_LOG( SG_GENERAL, SG_INFO, 
 	  "Ra = (" << (SGD_RADIANS_TO_DEGREES *rightAscension) 
-- 
2.39.5