diff -ruNp kstars-4.12.2-orig/kstars/skyobjects/ksmoon.cpp kstars-4.12.2/kstars/skyobjects/ksmoon.cpp
--- kstars-4.12.2-orig/kstars/skyobjects/ksmoon.cpp	2014-01-05 06:50:17.000000000 -0500
+++ kstars-4.12.2/kstars/skyobjects/ksmoon.cpp	2014-02-18 18:26:24.000000000 -0500
@@ -227,7 +227,7 @@ void KSMoon::findMagnitude(const KSNumbe
     // relevant data put into ksplanetbase.h) was taken from
     // SkyChart v3 Beta
     double phd = phase().Degrees();
-    if( isnan( phd ) ) // Avoid nanny phases.
+    if( std::isnan( phd ) ) // Avoid nanny phases.
         return;
     int p = floor( phd );
     if( p > 180 )