Neue Seite: Sonnensystem-Baryzentrum

Zeigt die Bewegung des gemeinsamen Schwerpunkts von Sonne und Planeten
von 2006 bis 2050 als animierte Canvas-Darstellung. Vergangener Pfad
in Cyan, Prognose gestrichelt in Gold. Planetenbeiträge aller 8 Planeten
(gewichtet nach Masse × Abstand) als Balkendiagramm.

Berechnung via astronomy-engine (Python), neuer API-Action `barycenter`.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/auth_helpers.php

@@ -138,5 +138,6 @@ function manageablePublicPages(): array
         'satellitenhimmel.php' => 'Satellitenhimmel',
         'asteroid_temp.php' => 'Asteroid-Temperatur',
         'universesandbox.php' => 'Universe Sandbox',
+        'barycenter.php' => 'Baryzentrum',
     ];
 }

public/barycenter.php

@@ -0,0 +1,498 @@
+<?php
+declare(strict_types=1);
+session_start();
+
+require_once __DIR__ . '/python_api.php';
+
+$result = runPythonApi('barycenter', ['20', '12', '24']);
+
+
+require __DIR__ . '/header.php';
+?>
+
+<style>
+.bc-grid {
+    display: grid;
+    grid-template-columns: 1fr 1fr;
+    gap: 1.5rem;
+    align-items: start;
+}
+@media (max-width: 860px) {
+    .bc-grid { grid-template-columns: 1fr; }
+}
+
+#bc-canvas-wrap {
+    position: relative;
+    width: 100%;
+    aspect-ratio: 1;
+    background: #04060e;
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    overflow: hidden;
+}
+#bc-canvas {
+    display: block;
+    width: 100%;
+    height: 100%;
+}
+
+.bc-legend {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.5rem 1rem;
+    margin-top: 0.75rem;
+    font-size: 0.8rem;
+    color: var(--text-dim);
+}
+.bc-legend-item {
+    display: flex;
+    align-items: center;
+    gap: 0.4rem;
+}
+.bc-legend-dot {
+    width: 12px;
+    height: 12px;
+    border-radius: 50%;
+    flex-shrink: 0;
+}
+
+.bc-stat {
+    display: flex;
+    flex-direction: column;
+    gap: 0.2rem;
+    padding: 0.75rem 1rem;
+    background: var(--bg-card2);
+    border-radius: var(--radius);
+    border: 1px solid var(--border);
+}
+.bc-stat-label {
+    font-size: 0.75rem;
+    color: var(--text-dim);
+    letter-spacing: 0.05em;
+    text-transform: uppercase;
+}
+.bc-stat-value {
+    font-size: 1.2rem;
+    color: var(--gold-pale);
+    font-weight: 600;
+}
+.bc-stat-sub {
+    font-size: 0.8rem;
+    color: var(--text-dim);
+}
+
+.bc-stats-row {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
+    gap: 0.75rem;
+    margin-bottom: 1rem;
+}
+
+.bc-planet-bar-wrap {
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+}
+.bc-planet-row {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    font-size: 0.85rem;
+}
+.bc-planet-name {
+    width: 70px;
+    flex-shrink: 0;
+    color: var(--text-dim);
+}
+.bc-planet-bar-bg {
+    flex: 1;
+    height: 8px;
+    background: rgba(255,255,255,0.06);
+    border-radius: 4px;
+    overflow: hidden;
+}
+.bc-planet-bar {
+    height: 100%;
+    border-radius: 4px;
+    transition: width 0.8s ease;
+}
+.bc-planet-val {
+    width: 50px;
+    text-align: right;
+    color: var(--text-dim);
+    font-size: 0.78rem;
+}
+
+.bc-anim-controls {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    margin-top: 0.75rem;
+    flex-wrap: wrap;
+}
+.bc-year-label {
+    font-size: 0.85rem;
+    color: var(--gold-pale);
+    min-width: 60px;
+}
+input[type=range].bc-slider {
+    flex: 1;
+    min-width: 120px;
+    accent-color: var(--gold);
+    cursor: pointer;
+}
+
+.bc-inside-badge {
+    display: inline-block;
+    padding: 0.15em 0.6em;
+    border-radius: 20px;
+    font-size: 0.75rem;
+    font-weight: 600;
+    letter-spacing: 0.04em;
+}
+.bc-inside-badge.inside {
+    background: rgba(79,195,216,0.2);
+    color: var(--cyan);
+    border: 1px solid rgba(79,195,216,0.4);
+}
+.bc-inside-badge.outside {
+    background: rgba(201,168,76,0.15);
+    color: var(--gold);
+    border: 1px solid var(--border);
+}
+</style>
+
+<?php if (!$result['ok']): ?>
+<div class="card">
+    <p class="msg-error"><li>Fehler beim Berechnen: <?= htmlspecialchars($result['error'] ?? 'Unbekannter Fehler', ENT_QUOTES, 'UTF-8') ?></li></p>
+</div>
+<?php else:
+    $cur = $result['data']['current'];
+    $distSR = $cur['dist_solar_radii'];
+    $inside = $cur['inside_sun'];
+    $contributions = $result['data']['contributions'];
+?>
+
+<div class="bc-stats-row">
+    <div class="bc-stat">
+        <span class="bc-stat-label">Abstand vom Sonnenmittelpunkt</span>
+        <span class="bc-stat-value"><?= number_format($distSR, 3, ',', '') ?> R☉</span>
+        <span class="bc-stat-sub"><?= number_format($cur['dist_au'], 5, ',', '') ?> AU</span>
+    </div>
+    <div class="bc-stat">
+        <span class="bc-stat-label">Position</span>
+        <span class="bc-stat-value">
+            <span class="bc-inside-badge <?= $inside ? 'inside' : 'outside' ?>">
+                <?= $inside ? 'Innerhalb der Sonne' : 'Außerhalb der Sonne' ?>
+            </span>
+        </span>
+        <span class="bc-stat-sub">Stand: <?= htmlspecialchars($cur['date_utc'], ENT_QUOTES, 'UTF-8') ?></span>
+    </div>
+    <div class="bc-stat">
+        <span class="bc-stat-label">Maximum (2006–2050)</span>
+        <span class="bc-stat-value"><?= number_format($result['data']['max_dist_solar_radii'], 3, ',', '') ?> R☉</span>
+        <span class="bc-stat-sub">Maximaler Abstand im Zeitraum</span>
+    </div>
+</div>
+
+<div class="bc-grid">
+    <div>
+        <div class="card">
+            <h2>Bahnkurve des Baryzentrums</h2>
+            <div id="bc-canvas-wrap">
+                <canvas id="bc-canvas"></canvas>
+            </div>
+            <div class="bc-legend">
+                <span class="bc-legend-item"><span class="bc-legend-dot" style="background:#f5c842"></span> Sonne</span>
+                <span class="bc-legend-item"><span class="bc-legend-dot" style="background:rgba(255,255,255,0.25);border:1px dashed #666"></span> Sonnenoberfläche</span>
+                <span class="bc-legend-item"><span class="bc-legend-dot" style="background:#4fc3d8"></span> Baryzentrum (Vergangenheit)</span>
+                <span class="bc-legend-item"><span class="bc-legend-dot" style="background:#c9a84c;opacity:0.7"></span> Baryzentrum (Prognose)</span>
+                <span class="bc-legend-item"><span class="bc-legend-dot" style="background:#ff6060"></span> Baryzentrum (heute)</span>
+            </div>
+            <div class="bc-anim-controls">
+                <button id="bc-play" class="btn btn-sm btn-secondary">▶ Abspielen</button>
+                <input type="range" class="bc-slider" id="bc-slider" min="0" max="240" value="240" step="1">
+                <span class="bc-year-label" id="bc-year-label">heute</span>
+            </div>
+        </div>
+    </div>
+    <div>
+        <div class="card">
+            <h2>Erklärung</h2>
+            <p style="font-size:0.9rem;color:var(--text-dim);line-height:1.6">
+                Das <strong style="color:var(--text)">Baryzentrum</strong> ist der gemeinsame Schwerpunkt des gesamten Sonnensystems.
+                Die Sonne kreist – wie alle Planeten – um diesen Punkt, nicht umgekehrt.
+            </p>
+            <p style="font-size:0.9rem;color:var(--text-dim);line-height:1.6;margin-top:0.75rem">
+                Der Schwerpunkt liegt meist nahe der Sonnenoberfläche oder knapp darüber
+                (ca. 1&nbsp;Sonnenradius Abstand), selten direkt im Sonnenmittelpunkt.
+                <strong style="color:var(--gold)">Jupiter</strong> hat den bei weitem größten Einfluss.
+            </p>
+            <p style="font-size:0.9rem;color:var(--text-dim);line-height:1.6;margin-top:0.75rem">
+                Der dargestellte Zeitraum reicht von 2006 bis 2050 (Vergangenheit + Prognose).
+                Die Bahn folgt keinem einfachen Kreis –
+                die Überlagerung der Planetenumläufe erzeugt eine komplexe Spirale.
+            </p>
+        </div>
+
+        <div class="card" style="margin-top:1.5rem">
+            <h2>Planetenbeiträge (heliozentrisch)</h2>
+            <div class="bc-planet-bar-wrap">
+                <?php
+                $planetColors = [
+                    'Merkur'  => '#b0b0b0',
+                    'Venus'   => '#e8c97a',
+                    'Erde'    => '#4fc3d8',
+                    'Mars'    => '#e05050',
+                    'Jupiter' => '#c9a84c',
+                    'Saturn'  => '#d4a96a',
+                    'Uranus'  => '#7fd4e8',
+                    'Neptun'  => '#6a8fd8',
+                ];
+                $maxContrib = max(array_column($contributions, 'ssb_contribution_au'));
+                foreach ($contributions as $p):
+                    $pct = $maxContrib > 0 ? round($p['ssb_contribution_au'] / $maxContrib * 100, 1) : 0;
+                    $color = $planetColors[$p['name']] ?? '#888';
+                ?>
+                <div class="bc-planet-row">
+                    <span class="bc-planet-name"><?= htmlspecialchars($p['name'], ENT_QUOTES, 'UTF-8') ?></span>
+                    <div class="bc-planet-bar-bg">
+                        <div class="bc-planet-bar" style="width:<?= $pct ?>%;background:<?= $color ?>"></div>
+                    </div>
+                    <span class="bc-planet-val" title="<?= number_format($p['helio_dist_au'], 2, ',', '.') ?> AU Abstand"><?= $p['ssb_contribution_au'] >= 0.0001 ? number_format($p['ssb_contribution_au'], 4, ',', '') : '< 0,0001' ?> AU</span>
+                </div>
+                <?php endforeach; ?>
+            </div>
+            <p style="font-size:0.78rem;color:var(--text-dim);margin-top:0.9rem">
+                Balken zeigen den gewichteten Beitrag zum SSB-Offset (Masse × Abstand).
+                Jupiter dominiert mit ~71 % der gesamten Planetenmasse. Die inneren Planeten
+                (Merkur bis Mars) tragen zusammen weniger als 0,1 % bei.
+            </p>
+        </div>
+    </div>
+</div>
+
+<script>
+(function () {
+    const SERIES    = <?= json_encode($result['data']['series'], JSON_UNESCAPED_UNICODE) ?>;
+    const DATES     = <?= json_encode($result['data']['series_dates'], JSON_UNESCAPED_UNICODE) ?>;
+    const CUR       = <?= json_encode($cur, JSON_UNESCAPED_UNICODE) ?>;
+    const NOW_INDEX = <?= (int)$result['data']['now_index'] ?>;
+    const SUN_RADIUS_AU = <?= json_encode($result['data']['sun_radius_au']) ?>;
+    const MAX_DIST_SR   = <?= json_encode($result['data']['max_dist_solar_radii']) ?>;
+
+    const canvas = document.getElementById('bc-canvas');
+    const ctx    = canvas.getContext('2d');
+
+    let visibleUpTo = NOW_INDEX; // startet bei "heute"
+    let animPlaying = false;
+    let animFrame   = null;
+    let animIndex   = 0;
+
+    const slider    = document.getElementById('bc-slider');
+    const playBtn   = document.getElementById('bc-play');
+    const yearLabel = document.getElementById('bc-year-label');
+
+    slider.max = SERIES.length - 1;
+    slider.value = NOW_INDEX;
+
+    function formatDate(yearFrac) {
+        const y = Math.floor(yearFrac);
+        const m = Math.round((yearFrac - y) * 12) + 1;
+        return y + '-' + String(m).padStart(2, '0');
+    }
+
+    function resize() {
+        const wrap = document.getElementById('bc-canvas-wrap');
+        const size = wrap.clientWidth;
+        canvas.width  = size;
+        canvas.height = size;
+        draw();
+    }
+
+    function draw() {
+        const W = canvas.width;
+        const H = canvas.height;
+        const cx = W / 2;
+        const cy = H / 2;
+
+        // Scale: fit MAX_DIST_SR * 1.3 solar radii into half-canvas
+        const scale = (W * 0.42) / (MAX_DIST_SR * 1.15);
+        const sunRadiusPx = scale;  // 1 solar radius → scale px
+
+        ctx.clearRect(0, 0, W, H);
+
+        // Background grid rings
+        ctx.strokeStyle = 'rgba(255,255,255,0.05)';
+        ctx.lineWidth = 1;
+        for (let r = 1; r <= Math.ceil(MAX_DIST_SR * 1.2); r++) {
+            ctx.beginPath();
+            ctx.arc(cx, cy, r * scale, 0, Math.PI * 2);
+            ctx.stroke();
+        }
+        // Ring labels
+        ctx.font = '10px sans-serif';
+        ctx.fillStyle = 'rgba(255,255,255,0.25)';
+        ctx.textAlign = 'left';
+        for (let r = 1; r <= Math.ceil(MAX_DIST_SR * 1.2); r++) {
+            ctx.fillText(r + ' R☉', cx + r * scale + 3, cy - 3);
+        }
+
+        // Sun glow
+        const glow = ctx.createRadialGradient(cx, cy, 0, cx, cy, sunRadiusPx * 2.5);
+        glow.addColorStop(0,   'rgba(255, 220, 80, 0.6)');
+        glow.addColorStop(0.4, 'rgba(255, 180, 40, 0.25)');
+        glow.addColorStop(1,   'rgba(255, 140, 0, 0)');
+        ctx.beginPath();
+        ctx.arc(cx, cy, sunRadiusPx * 2.5, 0, Math.PI * 2);
+        ctx.fillStyle = glow;
+        ctx.fill();
+
+        // Sun disk
+        ctx.beginPath();
+        ctx.arc(cx, cy, sunRadiusPx, 0, Math.PI * 2);
+        ctx.fillStyle = '#f5c842';
+        ctx.fill();
+
+        // Sun surface dashed circle
+        ctx.beginPath();
+        ctx.arc(cx, cy, sunRadiusPx, 0, Math.PI * 2);
+        ctx.setLineDash([4, 4]);
+        ctx.strokeStyle = 'rgba(255,255,255,0.2)';
+        ctx.lineWidth = 1;
+        ctx.stroke();
+        ctx.setLineDash([]);
+
+        // Barycenter path up to visibleUpTo
+        const end = Math.min(visibleUpTo, SERIES.length - 1);
+
+        // Vergangener Pfad (bis NOW_INDEX) — cyan
+        const pastEnd = Math.min(end, NOW_INDEX);
+        if (pastEnd >= 1) {
+            ctx.beginPath();
+            const p0 = SERIES[0];
+            ctx.moveTo(cx + p0.x / SUN_RADIUS_AU * scale, cy - p0.y / SUN_RADIUS_AU * scale);
+            for (let i = 1; i <= pastEnd; i++) {
+                const p = SERIES[i];
+                ctx.lineTo(cx + p.x / SUN_RADIUS_AU * scale, cy - p.y / SUN_RADIUS_AU * scale);
+            }
+            ctx.strokeStyle = 'rgba(79, 195, 216, 0.55)';
+            ctx.lineWidth = 1.5;
+            ctx.setLineDash([]);
+            ctx.stroke();
+        }
+
+        // Zukünftiger Pfad (ab NOW_INDEX) — gold gedimmt, gestrichelt
+        if (end > NOW_INDEX) {
+            ctx.beginPath();
+            const pn = SERIES[NOW_INDEX];
+            ctx.moveTo(cx + pn.x / SUN_RADIUS_AU * scale, cy - pn.y / SUN_RADIUS_AU * scale);
+            for (let i = NOW_INDEX + 1; i <= end; i++) {
+                const p = SERIES[i];
+                ctx.lineTo(cx + p.x / SUN_RADIUS_AU * scale, cy - p.y / SUN_RADIUS_AU * scale);
+            }
+            ctx.strokeStyle = 'rgba(201, 168, 76, 0.45)';
+            ctx.lineWidth = 1.5;
+            ctx.setLineDash([5, 4]);
+            ctx.stroke();
+            ctx.setLineDash([]);
+        }
+
+        // Current SSB dot
+        const pCur = SERIES[end];
+        const px = cx + pCur.x / SUN_RADIUS_AU * scale;
+        const py = cy - pCur.y / SUN_RADIUS_AU * scale;
+
+        // Dot glow
+        const dotGlow = ctx.createRadialGradient(px, py, 0, px, py, 10);
+        dotGlow.addColorStop(0, 'rgba(255, 80, 80, 0.8)');
+        dotGlow.addColorStop(1, 'rgba(255, 80, 80, 0)');
+        ctx.beginPath();
+        ctx.arc(px, py, 10, 0, Math.PI * 2);
+        ctx.fillStyle = dotGlow;
+        ctx.fill();
+
+        ctx.beginPath();
+        ctx.arc(px, py, 4, 0, Math.PI * 2);
+        ctx.fillStyle = '#ff6060';
+        ctx.fill();
+
+        // Distance label
+        ctx.font = '11px sans-serif';
+        ctx.fillStyle = 'rgba(255,255,255,0.65)';
+        ctx.textAlign = 'left';
+        ctx.fillText(pCur.d.toFixed(3) + ' R☉', px + 8, py - 6);
+    }
+
+    function updateLabel() {
+        const idx = parseInt(slider.value, 10);
+        if (idx === NOW_INDEX) {
+            yearLabel.textContent = 'heute';
+        } else {
+            yearLabel.textContent = formatDate(DATES[idx]);
+        }
+    }
+
+    slider.addEventListener('input', () => {
+        visibleUpTo = parseInt(slider.value, 10);
+        updateLabel();
+        draw();
+        if (animPlaying) stopAnim();
+    });
+
+    function stopAnim() {
+        animPlaying = false;
+        playBtn.textContent = '▶ Abspielen';
+        if (animFrame) { cancelAnimationFrame(animFrame); animFrame = null; }
+    }
+
+    function startAnim() {
+        animPlaying = true;
+        playBtn.textContent = '⏸ Pause';
+        // Start from beginning if at or near end
+        if (visibleUpTo >= SERIES.length - 1) {
+            visibleUpTo = 0;
+            animIndex = 0;
+        } else {
+            animIndex = visibleUpTo;
+        }
+
+        let last = null;
+        const msPerStep = 30; // ~33 fps, 1 step per frame
+        function step(ts) {
+            if (!animPlaying) return;
+            if (last === null || ts - last >= msPerStep) {
+                last = ts;
+                animIndex++;
+                if (animIndex >= SERIES.length) {
+                    animIndex = SERIES.length - 1;
+                    visibleUpTo = animIndex;
+                    slider.value = animIndex;
+                    updateLabel();
+                    draw();
+                    stopAnim();
+                    return;
+                }
+                visibleUpTo = animIndex;
+                slider.value = animIndex;
+                updateLabel();
+                draw();
+            }
+            animFrame = requestAnimationFrame(step);
+        }
+        animFrame = requestAnimationFrame(step);
+    }
+
+    playBtn.addEventListener('click', () => {
+        if (animPlaying) { stopAnim(); } else { startAnim(); }
+    });
+
+    window.addEventListener('resize', resize);
+    resize();
+    updateLabel();
+})();
+</script>
+
+<?php endif; ?>
+
+<?php require __DIR__ . '/footer.php'; ?>

public/header.php

@@ -154,6 +154,7 @@ $menuGroups = [
             ['href' => 'planetensichtbarkeit.php', 'label' => 'Planetensichtbarkeit'],
             ['href' => 'ephemeriden.php',           'label' => 'Ephemeriden'],
             ['href' => 'solarsystem.php',           'label' => 'Sonnensystem'],
+            ['href' => 'barycenter.php',             'label' => 'Baryzentrum'],
             ['href' => 'mars.php',                  'label' => 'Mars'],
             ['href' => 'jupitersystem.php',         'label' => 'Jupitersystem'],
             ['href' => 'asteroid_temp.php',         'label' => 'Asteroid-Temperatur'],

public/py/api.py

@@ -5505,6 +5505,122 @@ def action_satellite_passes(args: list[str]) -> dict:
     }
 
 
+_SUN_RADIUS_AU = 0.00465047  # 1 Sonnenradius in AU
+
+
+def action_barycenter(args: list[str]) -> dict:
+    """Berechnet SSB-Position relativ zur Sonne: aktuell, Zeitreihe, Planetenbeiträge."""
+    # Argumente: years_back, steps_per_year, years_forward
+    years_back = int(args[0]) if len(args) > 0 and args[0].isdigit() else 20
+    steps_per_year = int(args[1]) if len(args) > 1 and args[1].isdigit() else 12
+    years_forward = int(args[2]) if len(args) > 2 and args[2].isdigit() else 0
+    years_back = max(1, min(years_back, 100))
+    steps_per_year = max(4, min(steps_per_year, 52))
+    years_forward = max(0, min(years_forward, 100))
+
+    now = datetime.now(timezone.utc)
+    now_time = dt_to_time(now)
+
+    # -- Aktuelle Position --
+    sun_state = astronomy.BaryState(astronomy.Body.Sun, now_time)
+    # BaryState(Sun) = Position der Sonne relativ zum SSB → negieren = SSB relativ zur Sonne
+    cur_x = -sun_state.x
+    cur_y = -sun_state.y
+    cur_dist_au = math.hypot(cur_x, cur_y, -sun_state.z)
+    cur_dist_sr = cur_dist_au / _SUN_RADIUS_AU
+
+    # -- Zeitreihe --
+    total_steps = (years_back + years_forward) * steps_per_year
+    days_per_step = 365.25 / steps_per_year
+    start_jd = now_time.tt - years_back * 365.25
+    series = []
+    max_dist_au = 0.0
+    for i in range(total_steps + 1):
+        t = astronomy.Time(start_jd + i * days_per_step)
+        s = astronomy.BaryState(astronomy.Body.Sun, t)
+        tx, ty = -s.x, -s.y
+        d = math.hypot(tx, ty, -s.z)
+        if d > max_dist_au:
+            max_dist_au = d
+        dt_utc = datetime(2000, 1, 1, 12, tzinfo=timezone.utc) + timedelta(days=t.tt - 0.0)
+        # Epoche J2000.0 = 2000-01-01 12:00 TT ≈ UTC (Differenz <1 min hier vernachlässigt)
+        series.append({"x": round(tx, 6), "y": round(ty, 6), "d": round(d / _SUN_RADIUS_AU, 3)})
+
+    # Zeitstempel für Animationslabel (nur Jahr.Monat reicht)
+    series_dates = []
+    for i in range(total_steps + 1):
+        t_days = start_jd + i * days_per_step
+        # Grobe Umrechnung J2000-TT → Jahr
+        year_frac = 2000.0 + (t_days / 365.25)
+        series_dates.append(round(year_frac, 3))
+
+    # -- Planetenmassen (GM relativ zur Sonne = 1) für gewichteten Beitrag --
+    # Quellen: IAU 2012 / astronomy-engine Konstanten
+    _PLANET_MASS_FRACTION = {
+        astronomy.Body.Mercury: 1.6601e-7,
+        astronomy.Body.Venus:   2.4478e-6,
+        astronomy.Body.Earth:   3.0034e-6,   # inkl. Mond
+        astronomy.Body.Mars:    3.2272e-7,
+        astronomy.Body.Jupiter: 9.5479e-4,
+        astronomy.Body.Saturn:  2.8589e-4,
+        astronomy.Body.Uranus:  4.3662e-5,
+        astronomy.Body.Neptune: 5.1514e-5,
+    }
+
+    contrib_bodies = [
+        (astronomy.Body.Mercury, "Merkur"),
+        (astronomy.Body.Venus,   "Venus"),
+        (astronomy.Body.Earth,   "Erde"),
+        (astronomy.Body.Mars,    "Mars"),
+        (astronomy.Body.Jupiter, "Jupiter"),
+        (astronomy.Body.Saturn,  "Saturn"),
+        (astronomy.Body.Uranus,  "Uranus"),
+        (astronomy.Body.Neptune, "Neptun"),
+    ]
+    contributions = []
+    for body, name in contrib_bodies:
+        s = astronomy.BaryState(body, now_time)
+        hx = s.x - sun_state.x
+        hy = s.y - sun_state.y
+        hz = s.z - sun_state.z
+        helio_dist = math.hypot(hx, hy, hz)
+        bary_dist = math.hypot(s.x, s.y, s.z)
+        mass_frac = _PLANET_MASS_FRACTION.get(body, 0.0)
+        # Beitrag zum SSB-Offset = Masse × heliozentrischer Abstand (in AU)
+        ssb_contribution_au = mass_frac * helio_dist
+        contributions.append({
+            "name": name,
+            "helio_dist_au": round(helio_dist, 4),
+            "bary_dist_au": round(bary_dist, 4),
+            "bary_x": round(s.x, 6),
+            "bary_y": round(s.y, 6),
+            "mass_fraction": mass_frac,
+            "ssb_contribution_au": round(ssb_contribution_au, 8),
+        })
+
+    now_index = years_back * steps_per_year
+
+    return {
+        "ok": True,
+        "current": {
+            "x": round(cur_x, 6),
+            "y": round(cur_y, 6),
+            "dist_au": round(cur_dist_au, 6),
+            "dist_solar_radii": round(cur_dist_sr, 4),
+            "inside_sun": cur_dist_sr <= 1.0,
+            "date_utc": now.strftime("%Y-%m-%dT%H:%M:%SZ"),
+        },
+        "series": series,
+        "series_dates": series_dates,
+        "now_index": now_index,
+        "max_dist_solar_radii": round(max_dist_au / _SUN_RADIUS_AU, 3),
+        "sun_radius_au": _SUN_RADIUS_AU,
+        "contributions": contributions,
+        "years_back": years_back,
+        "years_forward": years_forward,
+    }
+
+
 def main() -> None:
     if len(sys.argv) < 2:
         fail("Es wurde keine Aktion uebergeben.", extra={"available_actions": ["sun_moon_rise_set", "solar_longitude_to_datetime", "current_solar_longitude", "astronomical_conversions", "comet_brightnesses", "favorite_comet_events_for_month", "moon_star_occultations", "moon_phase_details", "satellite_passes", "planet_rise_set", "planet_ephemeris", "month_sky_context", "moon_phases_for_month", "golden_handle_for_month", "season_changes_for_month", "time_changes_for_month", "moon_planet_approaches", "moon_deep_sky_approaches_for_month", "planet_bright_star_approaches_for_month", "golden_gate_of_ecliptic_for_month", "planet_conjunctions_for_month", "eclipses_for_month", "moon_apsides_for_month", "sun_apsides_for_month", "inner_planet_elongations_for_month", "venus_peak_magnitude_for_month", "outer_planet_events_for_month", "outer_planet_stations_for_month", "jupiter_moons_one_side_for_month", "mercury_good_visibility_for_month", "planet_parades_for_month", "planet_constellation_changes_for_month", "moon_star_occultations_for_month"]})
@@ -5687,6 +5803,11 @@ def main() -> None:
         print(json.dumps(result, ensure_ascii=True))
         return
 
+    if action == "barycenter":
+        result = action_barycenter(args)
+        print(json.dumps(result, ensure_ascii=True))
+        return
+
     fail("Unbekannte Aktion.", extra={"action": action, "available_actions": ["sun_moon_rise_set", "solar_longitude_to_datetime", "current_solar_longitude", "astronomical_conversions", "comet_brightnesses", "favorite_comet_events_for_month", "moon_star_occultations", "moon_phase_details", "satellite_passes", "planet_rise_set", "planet_ephemeris", "planet_visibility_chart", "month_sky_context", "moon_phases_for_month", "golden_handle_for_month", "season_changes_for_month", "time_changes_for_month", "moon_planet_approaches", "moon_deep_sky_approaches_for_month", "planet_bright_star_approaches_for_month", "golden_gate_of_ecliptic_for_month", "planet_conjunctions_for_month", "eclipses_for_month", "moon_apsides_for_month", "sun_apsides_for_month", "inner_planet_elongations_for_month", "venus_peak_magnitude_for_month", "outer_planet_events_for_month", "outer_planet_stations_for_month", "jupiter_moons_one_side_for_month", "mercury_good_visibility_for_month", "planet_parades_for_month", "planet_constellation_changes_for_month", "moon_star_occultations_for_month"]})