diff --git a/index.html b/index.html
index cdd53a2..d9c3a6d 100644
--- a/index.html
+++ b/index.html
@@ -577,6 +577,12 @@
                 getMoonPhaseText(moonIllum.phase) + ' ' + Math.round(moonIllum.fraction * 100) + '%';
             renderMoonPhaseIcon(moonIllum.phase);
             renderRpgMoon(moonIllum.phase);
+
+            // DEBUG
+            document.title = 'moon: ' + (moonPos.isVisible ? 'visible' : 'hidden') +
+                ' rise=' + formatTimeHM(moonTimes.rise) +
+                ' set=' + formatTimeHM(moonTimes.set) +
+                ' now=' + formatTimeHM(now);
         }
 
         var startTime = Date.now();