diff --git a/src/cluster.c b/src/cluster.c
index e491af7..2184ccd 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -10,6 +10,15 @@ hexagram_cluster *hexagram_cluster_new(double width, double height) {
         goto error_malloc_cluster;
     }
 
+    /*
+     * Ensure correct cluster aspect ratio
+     */
+    if (width / height > 32.0 / 15.0) {
+        width = height * (32.0 / 15.0);
+    } else {
+        height = width * (15.0 / 32.0);
+    }
+
     hexagram_tacho_init(&cluster->tacho,
                         width  * 0.2,
                         height * 0.5,