diff --git a/libastro/anomaly.c b/libastro/anomaly.c
index 32b1d8d..bba83e4 100644
--- a/libastro/anomaly.c
+++ b/libastro/anomaly.c
@@ -6,7 +6,6 @@
 #include "astro.h"
 
 
-#define TWOPI   	(2*PI)
 #define	STOPERR		(1e-8)
 
 /* given the mean anomaly, ma, and the eccentricity, s, of elliptical motion,