diff --git a/CEP/BB/BBSKernel/src/MNS/MeqGaussianCoherency.cc b/CEP/BB/BBSKernel/src/MNS/MeqGaussianCoherency.cc
index d68069a3c52a78dbdc12c5cb9e08ef17a107f7f8..5626b0a86e5b095d16f8de936a429e28a9b782de 100644
--- a/CEP/BB/BBSKernel/src/MNS/MeqGaussianCoherency.cc
+++ b/CEP/BB/BBSKernel/src/MNS/MeqGaussianCoherency.cc
@@ -28,6 +28,7 @@
 #include <Common/lofar_complex.h>
 #include <Common/lofar_math.h>
 #include <Common/LofarLogger.h>
+#include <casa/BasicSL/Constants.h>
 
 using namespace casa;