diff --git a/public/ephemeriden.php b/public/ephemeriden.php
index ff9111e..4fcf7aa 100644
--- a/public/ephemeriden.php
+++ b/public/ephemeriden.php
@@ -334,15 +334,6 @@ $intervalOptions = [
     '43200' => '30 Tage',
 ];
 
-$rangeUnitOptions = [
-    'minutes' => 'Minuten',
-    'hours' => 'Stunden',
-    'days' => 'Tage',
-    'weeks' => 'Wochen',
-    'months' => 'Monate',
-    'years' => 'Jahre',
-];
-
 $selectedBody = (string) ($_POST['body'] ?? 'Mercury');
 if (!isset($bodyOptions[$selectedBody])) {
     $selectedBody = 'Mercury';
@@ -353,22 +344,16 @@ if (!isset($intervalOptions[$selectedInterval])) {
     $selectedInterval = '1440';
 }
 
-$selectedRangeUnit = (string) ($_POST['range_unit'] ?? 'days');
-if (!isset($rangeUnitOptions[$selectedRangeUnit])) {
-    $selectedRangeUnit = 'days';
-}
-
-$rangeValueInput = trim((string) ($_POST['range_value'] ?? '7'));
-if ($rangeValueInput === '') {
-    $rangeValueInput = '7';
-}
-
 $startDtInput = trim((string) ($_POST['start_dt'] ?? ''));
-// Validierung: muss leer sein (= jetzt) oder dem Format YYYY-MM-DDTHH:MM entsprechen
 if ($startDtInput !== '' && !preg_match('/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}$/', $startDtInput)) {
     $startDtInput = '';
 }
 
+$endDtInput = trim((string) ($_POST['end_dt'] ?? ''));
+if ($endDtInput !== '' && !preg_match('/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}$/', $endDtInput)) {
+    $endDtInput = '';
+}
+
 function ephemeriden_h(mixed $value): string
 {
     return htmlspecialchars((string) $value, ENT_QUOTES, 'UTF-8');
@@ -449,51 +434,63 @@ $exportFormat = (string) ($_POST['export_format'] ?? '');
 if ($_SERVER['REQUEST_METHOD'] === 'POST') {
     if ($pageLocation === null || $pageLocation['latitude'] === null || $pageLocation['longitude'] === null) {
         $errorMessage = 'Kein gültiger Standard-Standort verfügbar. Bitte zuerst in den Einstellungen einen Standard-Standort setzen.';
-    } elseif (!ctype_digit($rangeValueInput) || (int) $rangeValueInput < 1 || (int) $rangeValueInput > 100) {
-        $errorMessage = 'Der Zeitraum muss als ganze Zahl zwischen 1 und 100 angegeben werden.';
+    } elseif ($endDtInput === '') {
+        $errorMessage = 'Bitte ein Enddatum angeben.';
     } else {
-        $pythonAction = 'planet_ephemeris';
-        $pythonArgs = [
-            (string) $pageLocation['latitude'],
-            (string) $pageLocation['longitude'],
-            (string) $pageLocation['elevation'],
-            (string) $pageLocation['timezone'],
-            $selectedBody,
-            $selectedInterval,
-            $rangeValueInput,
-            $selectedRangeUnit,
-            $startDtInput,
-        ];
+        $tz = new DateTimeZone($pageLocation['timezone']);
+        $startDt = $startDtInput !== ''
+            ? DateTimeImmutable::createFromFormat('Y-m-d\TH:i', $startDtInput, $tz)
+            : new DateTimeImmutable('now', $tz);
+        $endDt = DateTimeImmutable::createFromFormat('Y-m-d\TH:i', $endDtInput, $tz);
 
-        if (isset($minorplanetPayloads[$selectedBody])) {
-            $pythonAction = 'small_body_ephemeris';
+        if ($startDt === false || $endDt === false) {
+            $errorMessage = 'Start- oder Enddatum ist ungültig.';
+        } elseif ($endDt <= $startDt) {
+            $errorMessage = 'Das Enddatum muss nach dem Startdatum liegen.';
+        } else {
+            $rangeMinutes = (string) (int) round(($endDt->getTimestamp() - $startDt->getTimestamp()) / 60);
+            $pythonAction = 'planet_ephemeris';
             $pythonArgs = [
                 (string) $pageLocation['latitude'],
                 (string) $pageLocation['longitude'],
                 (string) $pageLocation['elevation'],
                 (string) $pageLocation['timezone'],
-                'minorplanet',
-                base64_encode(json_encode($minorplanetPayloads[$selectedBody], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) ?: '{}'),
+                $selectedBody,
                 $selectedInterval,
-                $rangeValueInput,
-                $selectedRangeUnit,
+                $rangeMinutes,
+                'minutes',
                 $startDtInput,
             ];
-        } elseif (isset($cometPayloads[$selectedBody])) {
-            $pythonAction = 'small_body_ephemeris';
-            $pythonArgs = [
-                (string) $pageLocation['latitude'],
-                (string) $pageLocation['longitude'],
-                (string) $pageLocation['elevation'],
-                (string) $pageLocation['timezone'],
-                'comet',
-                base64_encode(json_encode($cometPayloads[$selectedBody], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) ?: '{}'),
-                $selectedInterval,
-                $rangeValueInput,
-                $selectedRangeUnit,
-                $startDtInput,
-            ];
-        }
+
+            if (isset($minorplanetPayloads[$selectedBody])) {
+                $pythonAction = 'small_body_ephemeris';
+                $pythonArgs = [
+                    (string) $pageLocation['latitude'],
+                    (string) $pageLocation['longitude'],
+                    (string) $pageLocation['elevation'],
+                    (string) $pageLocation['timezone'],
+                    'minorplanet',
+                    base64_encode(json_encode($minorplanetPayloads[$selectedBody], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) ?: '{}'),
+                    $selectedInterval,
+                    $rangeMinutes,
+                    'minutes',
+                    $startDtInput,
+                ];
+            } elseif (isset($cometPayloads[$selectedBody])) {
+                $pythonAction = 'small_body_ephemeris';
+                $pythonArgs = [
+                    (string) $pageLocation['latitude'],
+                    (string) $pageLocation['longitude'],
+                    (string) $pageLocation['elevation'],
+                    (string) $pageLocation['timezone'],
+                    'comet',
+                    base64_encode(json_encode($cometPayloads[$selectedBody], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) ?: '{}'),
+                    $selectedInterval,
+                    $rangeMinutes,
+                    'minutes',
+                    $startDtInput,
+                ];
+            }
 
         $pythonResult = runEphemeridenPythonApi($pythonAction, $pythonArgs);
 
@@ -544,6 +541,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                 exit;
             }
         }
+        }
     }
 }
 
@@ -781,33 +779,21 @@ require __DIR__ . '/header.php';
                     type="datetime-local"
                     id="ephemeridenStartDt"
                     name="start_dt"
-                    value="<?= ephemeriden_h($startDtInput) ?>"
+                    value="<?= ephemeriden_h($startDtInput !== '' ? $startDtInput : (new DateTimeImmutable('now', new DateTimeZone($pageLocation['timezone'] ?? 'Europe/Berlin')))->format('Y-m-d\TH:i')) ?>"
                 >
             </div>
 
             <div class="form-group">
-                <label for="ephemeridenRangeValue">Zeitraum</label>
+                <label for="ephemeridenEndDt">Enddatum &amp; Uhrzeit</label>
                 <input
-                    type="number"
-                    id="ephemeridenRangeValue"
-                    name="range_value"
-                    min="1"
-                    max="100"
-                    step="1"
-                    value="<?= ephemeriden_h($rangeValueInput) ?>"
-                    inputmode="numeric"
+                    type="datetime-local"
+                    id="ephemeridenEndDt"
+                    name="end_dt"
+                    value="<?= ephemeriden_h($endDtInput !== '' ? $endDtInput : (new DateTimeImmutable('+7 days', new DateTimeZone($pageLocation['timezone'] ?? 'Europe/Berlin')))->format('Y-m-d\TH:i')) ?>"
+                    required
                 >
             </div>
 
-            <div class="form-group">
-                <label for="ephemeridenRangeUnit">Einheit</label>
-                <select id="ephemeridenRangeUnit" name="range_unit">
-                    <?php foreach ($rangeUnitOptions as $rangeUnitValue => $rangeUnitLabel): ?>
-                        <option value="<?= ephemeriden_h($rangeUnitValue) ?>"<?= $rangeUnitValue === $selectedRangeUnit ? ' selected' : '' ?>><?= ephemeriden_h($rangeUnitLabel) ?></option>
-                    <?php endforeach; ?>
-                </select>
-            </div>
-
             <div class="ephemeriden-submit-group">
                 <button type="submit" class="btn btn-primary">Berechnen</button>
             </div>