diff --git a/public/index.php b/public/index.php
index 20368f6..d7d4429 100644
--- a/public/index.php
+++ b/public/index.php
@@ -106,18 +106,23 @@ if (!function_exists('planetVisibilityClass')) {
 
         $astroDusk = eventDateTime($ev['astro_dusk'] ?? []);
         $astroDawnNext = eventDateTime($evNext['astro_dawn'] ?? []);
+        $nauticalDusk = eventDateTime($ev['nautical_dusk'] ?? []);
         $civilDusk = eventDateTime($ev['civil_dusk'] ?? []);
+        $nauticalDawnNext = eventDateTime($evNext['nautical_dawn'] ?? []);
         $civilDawnNext = eventDateTime($evNext['civil_dawn'] ?? []);
 
         $nightSeconds = 0;
+        $nauticalSeconds = 0;
         $twilightSeconds = 0;
         $visibleSeconds = 0;
 
         foreach ($intervals as [$from, $to]) {
             $visibleSeconds += intervalDurationSeconds($from, $to);
             $nightSeconds += intervalOverlapSeconds($from, $to, $astroDusk, $astroDawnNext);
-            $twilightSeconds += intervalOverlapSeconds($from, $to, $civilDusk, $astroDusk);
-            $twilightSeconds += intervalOverlapSeconds($from, $to, $astroDawnNext, $civilDawnNext);
+            $nauticalSeconds += intervalOverlapSeconds($from, $to, $nauticalDusk, $astroDusk);
+            $nauticalSeconds += intervalOverlapSeconds($from, $to, $astroDawnNext, $nauticalDawnNext);
+            $twilightSeconds += intervalOverlapSeconds($from, $to, $civilDusk, $nauticalDusk);
+            $twilightSeconds += intervalOverlapSeconds($from, $to, $nauticalDawnNext, $civilDawnNext);
         }
 
         if ($visibleSeconds <= 0) {
@@ -125,11 +130,24 @@ if (!function_exists('planetVisibilityClass')) {
         }
 
         $nightRatio = $nightSeconds / $visibleSeconds;
+        $darkRatio = ($nightSeconds + $nauticalSeconds) / $visibleSeconds;
 
         if ($nightSeconds >= 3600 && $nightRatio >= 0.35) {
             return ['class' => 'planet-visibility-good', 'label' => 'nachts gut sichtbar'];
         }
 
+        if (($nightSeconds + $nauticalSeconds) >= 5400 && $darkRatio >= 0.35) {
+            return ['class' => 'planet-visibility-good', 'label' => 'in dunkler Daemmerung gut sichtbar'];
+        }
+
+        if ($nightSeconds > 0) {
+            return ['class' => 'planet-visibility-warn', 'label' => 'nur teilweise in der astronomischen Nacht'];
+        }
+
+        if ($nauticalSeconds > 0) {
+            return ['class' => 'planet-visibility-warn', 'label' => 'nur in nautischer Daemmerung sichtbar'];
+        }
+
         if (($nightSeconds + $twilightSeconds) > 0) {
             return ['class' => 'planet-visibility-warn', 'label' => 'nur teilweise nachts / in der Dämmerung'];
         }