From 372fffd3769af0909e58a4780cc3731677b80fc8 Mon Sep 17 00:00:00 2001
From: KaiSD <kaisd@noreply.example.org>
Date: Wed, 26 Feb 2025 12:51:36 +0100
Subject: [PATCH] =?UTF-8?q?=D0=98=D0=B7=D0=BC=D0=B5=D0=BD=D0=B8=D1=82?=
 =?UTF-8?q?=D1=8C=20'wbld/orbits.html'?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 wbld/orbits.html | 385 +++++++++++++++++++++++++++++++----------------
 1 file changed, 257 insertions(+), 128 deletions(-)
diff --git a/wbld/orbits.html b/wbld/orbits.html
index c30a52a..c656d1c 100644
--- a/wbld/orbits.html
+++ b/wbld/orbits.html
@@ -2,12 +2,12 @@
 <html lang="en">
 <head>
   <meta charset="UTF-8">
-  <title>Senthara Orbit, Rotation, Day/Night & Elliptical Orbits</title>
+  <title>Senthara Orbit, Rotation, Phases & Astronomical Data</title>
   <script src="https://cdn.jsdelivr.net/npm/phaser@3.60.0/dist/phaser.js"></script>
   <style>
     body { margin: 0; overflow: hidden; }
     canvas { display: block; }
-    /* Style for the control panel */
+    /* Control panel style */
     #controlPanel {
       position: absolute;
       bottom: 10px;
@@ -34,32 +34,88 @@
 </head>
 <body>
   <div id="controlPanel">
-      <button id="playPauseButton">Play</button>
-      <button id="rewindButton">Rewind</button>
-      <select id="speedSelect">
-          <option value="1">x1</option>
-          <option value="2">x2</option>
-          <option value="5" selected>x5</option>
-          <option value="10">x10</option>
-          <option value="100">x100</option>
-          <option value="1000">x1000</option>
-          <option value="10000">x10000</option>
-          <option value="100000">x100000</option>
-          <option value="1000000">x1000000</option>
-      </select>
+    <button id="playPauseButton">Play</button>
+    <button id="rewindButton">Rewind</button>
+    <select id="speedSelect">
+      <option value="1">x1</option>
+      <option value="2">x2</option>
+      <option value="5" selected>x5</option>
+      <option value="10">x10</option>
+      <option value="100">x100</option>
+      <option value="1000">x1000</option>
+    </select>
   </div>
   <script>
-    // Helper: returns {x, y} for an elliptical orbit.
-    // a = semi-major axis, ecc = eccentricity, so semi-minor axis b = a*sqrt(1 - ecc^2).
-    // theta is a linear parameter based on simulation time (not the true anomaly, but sufficient for visualization).
+    /////////////////////////////
+    // 1. Geometry and Moon Phases
+    /////////////////////////////
+
+    /**
+     * Returns {x, y} for an elliptical orbit.
+     * a = semi-major axis, ecc = eccentricity, b = a*sqrt(1-ecc^2).
+     * Theta is computed linearly from simulation time.
+     */
     function getEllipticalPosition(simTime, period, a, ecc) {
-      const theta = Phaser.Math.DegToRad((360 * (simTime % period)) / period - 90);
+      const thetaDeg = (360 * (simTime % period)) / period - 90;
+      const theta = Phaser.Math.DegToRad(thetaDeg);
       const b = a * Math.sqrt(1 - ecc * ecc);
       return { x: a * Math.cos(theta), y: b * Math.sin(theta) };
     }
 
-    // Function to calculate the current Senthara date from simulationTime (in days),
-    // with an offset so that simulationTime=0 corresponds to "Autumn 36".
+    /**
+     * Compute the fraction of the moon's disc illuminated as seen from the planet.
+     * We define vectors:
+     *   M→S = (starX - moonX, starY - moonY)
+     *   M→P = (planetX - moonX, planetY - moonY)
+     * Then, litFraction = (1 + cos(alpha))/2, where alpha is the angle between M→S and M→P.
+     * When alpha=0, fraction=1 (full), when alpha=π, fraction=0 (new).
+     */
+    function getMoonLitFraction(moonX, moonY, starX, starY, planetX, planetY) {
+      const MSx = starX - moonX;
+      const MSy = starY - moonY;
+      const MPx = planetX - moonX;
+      const MPy = planetY - moonY;
+      const dot = MSx * MPx + MSy * MPy;
+      const magMS = Math.sqrt(MSx * MSx + MSy * MSy);
+      const magMP = Math.sqrt(MPx * MPx + MPy * MPy);
+      if (magMS < 1e-9 || magMP < 1e-9) return 0.0;
+      let cosAlpha = dot / (magMS * magMP);
+      cosAlpha = Math.max(-1, Math.min(1, cosAlpha));
+      return 1 - 0.5 * (1 + cosAlpha);
+    }
+
+    /**
+     * Given a lit fraction (0 to 1) and whether the moon is waxing, compute a phase emoji.
+     * We compute an effective phase angle:
+     *   phaseAngle = arccos(2*frac - 1) in degrees.
+     * If waning, effectivePhase = 360 - phaseAngle.
+     * Then divide the 360° into eight segments.
+     */
+    function getMoonPhaseEmoji(frac, waxing) {
+      // Compute phase angle in degrees.
+      let phaseAngle = Math.acos(2 * frac - 1) * (180 / Math.PI);
+      if (!waxing) {
+        phaseAngle = 360 - phaseAngle;
+      }
+      // Map phaseAngle to one of eight phases.
+      if (phaseAngle < 45) return "🌑";           // 0-45: New Moon
+      else if (phaseAngle < 90) return waxing ? "🌒" : "🌘";
+      else if (phaseAngle < 135) return waxing ? "🌓" : "🌗";
+      else if (phaseAngle < 180) return waxing ? "🌔" : "🌖";
+      else if (phaseAngle < 225) return "🌕";        // 180-225: Full Moon
+      else if (phaseAngle < 270) return waxing ? "🌔" : "🌖";
+      else if (phaseAngle < 315) return waxing ? "🌓" : "🌗";
+      else return waxing ? "🌒" : "🌘";
+    }
+
+    /////////////////////////////
+    // 2. Senthara Date and Cycle Info
+    /////////////////////////////
+
+    /**
+     * Returns the Senthara date as "Year X - <Season> Y".
+     * The epoch is offset so that simulationTime=0 corresponds to "Autumn 36".
+     */
     function getSentharaDate(simDays) {
       const offset = 134;
       const X = Math.floor(simDays + offset);
@@ -68,71 +124,82 @@
       const seasonIndex = Math.floor((dayOfYear - 1) / 99);
       const dayOfSeason = dayOfYear - seasonIndex * 99;
       const seasons = ["Summer", "Autumn", "Winter", "Spring"];
-      return `Year ${year} - ${seasons[seasonIndex]} ${dayOfSeason}`;
+      return `Year ${year} - ${seasons[seasonIndex]} Day ${dayOfSeason}`;
     }
 
-    // Phaser configuration (responsive)
+    /////////////////////////////
+    // 3. Phaser Setup
+    /////////////////////////////
+
     const config = {
       type: Phaser.AUTO,
       width: window.innerWidth,
       height: window.innerHeight,
       backgroundColor: "#000000",
-      scene: {
-        preload: preload,
-        create: create,
-        update: update
-      },
-      scale: {
-        mode: Phaser.Scale.RESIZE
-      }
+      scene: { preload, create, update },
+      scale: { mode: Phaser.Scale.RESIZE }
     };
 
     const game = new Phaser.Game(config);
 
     let globalGraphics;
-    let dateText;
-    let simulationTime = 0; // in days (simulation time)
+    let astroText;  // Header text (top-left)
+    let simulationTime = 0;  // in days
     let simulationSpeed = 5; // speed multiplier
-    let isPlaying = false;   // Start paused
-    let isRewinding = false; // Control forward/backward
+    let isPlaying = false;
+    let isRewinding = false;
 
     // Orbital periods (in days)
-    const planetPeriod = 396;  // Senthara's orbital year around its star
-    const planetRotationPeriod = 1; // Planet rotates fully in 1 day
+    const planetPeriod = 396;  // Planet's orbit around the star
+    const planetRotationPeriod = 1; // Planet rotates once per day
     const kerielPeriod = 27;
     const arkaenPeriod = 82;
     const minianPeriod = 98;
 
-    // Eccentricity parameters (0 = circle; higher values = more elliptical)
-    const planetEcc = 0.2;     // Planet's orbit eccentricity
-    const kerielEcc = 0.05;    // Moons tend to have near-circular orbits due to tidal locking
+    // Eccentricity values (0 = circle)
+    const planetEcc = 0.2;
+    const kerielEcc = 0.05;
     const arkaenEcc = 0.05;
     const minianEcc = 0.05;
 
-    // Orbital radii (semi-major axes) (computed relative to window size)
+    // Full cycle lengths
+    const shortCycleLen = 108486; // ~274 years
+    const longCycleLen  = 2386692; // ~6027 years
+
+    // Orbital radii (semi-major axes, computed relative to window size)
     let planetOrbitRadius, kerielOrbitRadius, arkaenOrbitRadius, minianOrbitRadius;
 
-    // Containers for the planet and the moons.
+    // Containers for the planet and moons.
     let planetContainer;
     let kerielContainer, arkaenContainer, minianContainer;
 
-    function preload() {
-      // No external assets are needed.
-    }
+    // Tilt indicator for planet's spin axis.
+    let tiltIndicator;
+    const tiltLength = 30;
+    const planetTiltDeg = 23.5;
+    const tiltIndicatorAngle = Phaser.Math.DegToRad(-90 + planetTiltDeg);
+
+    // Global star (sun) position.
+    let starX, starY;
+
+    // We'll store previous lit fraction values for waxing/waning detection.
+    let oldFracKeriel = 0, oldFracArkaen = 0, oldFracMinian = 0;
+
+    function preload() {}
 
     function create() {
       globalGraphics = this.add.graphics();
-
-      dateText = this.add.text(10, game.scale.height - 30, "", {
+      astroText = this.add.text(10, 10, "", {
         font: "20px Arial",
         fill: "#ffffff"
       });
 
       recalcOrbitRadii();
+      starX = this.cameras.main.width / 2;
+      starY = this.cameras.main.height / 2;
 
-      // Create container for Senthara (the planet)
+      // Create container for the planet.
       planetContainer = this.add.container(0, 0);
-      // Planet body (green circle) with a marker line.
       let planetBody = this.add.graphics();
       planetBody.fillStyle(0x00FF00, 1);
       planetBody.fillCircle(0, 0, 12);
@@ -143,7 +210,7 @@
       planetBody.strokePath();
       planetContainer.add(planetBody);
 
-      // Night overlay for day/night cycle (semi-transparent half-circle)
+      // Planet night overlay.
       let nightOverlay = this.add.graphics();
       nightOverlay.fillStyle(0x000000, 0.5);
       nightOverlay.slice(0, 0, 12, 0, Math.PI, false);
@@ -151,138 +218,200 @@
       planetContainer.nightOverlay = nightOverlay;
       planetContainer.add(nightOverlay);
 
-      // Create containers for each moon.
-      kerielContainer = createMoonContainer(this, 6, 0xFF0000); // Keriel: red
-      arkaenContainer = createMoonContainer(this, 5, 0x0000FF); // Arkaen: blue
-      minianContainer = createMoonContainer(this, 5, 0xFFFFFF);  // Minian: white
+      // Create moon containers.
+      kerielContainer = createMoonContainer(this, 6, 0xFF0000);
+      arkaenContainer = createMoonContainer(this, 5, 0x0000FF);
+      minianContainer = createMoonContainer(this, 5, 0xFFFFFF);
 
-      // UI Control Handlers
+      // Add night overlays for moons.
+      kerielContainer.add(createMoonNightOverlay(this, 6));
+      arkaenContainer.add(createMoonNightOverlay(this, 5));
+      minianContainer.add(createMoonNightOverlay(this, 5));
+
+      // Create tilt indicator.
+      tiltIndicator = this.add.graphics();
+
+      // UI event handlers.
       const playPauseButton = document.getElementById("playPauseButton");
       const rewindButton = document.getElementById("rewindButton");
       const speedSelect = document.getElementById("speedSelect");
 
       playPauseButton.addEventListener("click", () => {
-          isPlaying = !isPlaying;
-          playPauseButton.textContent = isPlaying ? "Pause" : "Play";
-          if (isPlaying) isRewinding = false;
+        isPlaying = !isPlaying;
+        playPauseButton.textContent = isPlaying ? "Pause" : "Play";
+        if (isPlaying) isRewinding = false;
       });
-
       rewindButton.addEventListener("click", () => {
-          isRewinding = !isRewinding;
-          rewindButton.textContent = isRewinding ? "Forward" : "Rewind";
-          if(isRewinding) isPlaying = false;
-          playPauseButton.textContent = "Play";
+        isRewinding = !isRewinding;
+        rewindButton.textContent = isRewinding ? "Forward" : "Rewind";
+        if (isRewinding) isPlaying = false;
+        playPauseButton.textContent = "Play";
       });
-
       speedSelect.addEventListener("change", () => {
-          simulationSpeed = parseFloat(speedSelect.value);
+        simulationSpeed = parseFloat(speedSelect.value);
       });
 
       this.scale.on('resize', (gameSize) => {
-          recalcOrbitRadii();
-          dateText.setPosition(10, gameSize.height - 30);
+        recalcOrbitRadii();
+        astroText.setPosition(10, 10);
+        starX = gameSize.width / 2;
+        starY = gameSize.height / 2;
       });
     }
 
-    // Helper function to create a moon container with a circular body and a marker.
+    // Helper: Create a moon container with a circular body and a marker.
     function createMoonContainer(scene, radius, color) {
-      let moonContainer = scene.add.container(0, 0);
-      let moonBody = scene.add.graphics();
-      moonBody.fillStyle(color, 1);
-      moonBody.fillCircle(0, 0, radius);
-      moonBody.lineStyle(2, 0x000000, 1);
-      moonBody.beginPath();
-      moonBody.moveTo(0, 0);
-      moonBody.lineTo(radius, 0);
-      moonBody.strokePath();
-      moonContainer.add(moonBody);
-      return moonContainer;
+      let container = scene.add.container(0, 0);
+      let body = scene.add.graphics();
+      body.fillStyle(color, 1);
+      body.fillCircle(0, 0, radius);
+      body.lineStyle(2, 0x000000, 1);
+      body.beginPath();
+      body.moveTo(0, 0);
+      body.lineTo(radius, 0);
+      body.strokePath();
+      container.add(body);
+      return container;
+    }
+
+    // Helper: Create a half-circle night overlay for a moon.
+    function createMoonNightOverlay(scene, radius) {
+      let overlay = scene.add.graphics();
+      overlay.fillStyle(0x000000, 0.5);
+      overlay.slice(0, 0, radius, 0, Math.PI, false);
+      overlay.fillPath();
+      return overlay;
     }
 
     // Recalculate orbital radii based on window size.
     function recalcOrbitRadii() {
       const minDim = Math.min(window.innerWidth, window.innerHeight);
-      planetOrbitRadius = minDim * 0.3;  // semi-major axis for planet orbit
+      planetOrbitRadius = minDim * 0.3;
       kerielOrbitRadius = planetOrbitRadius * 0.25;
       arkaenOrbitRadius = planetOrbitRadius * 0.35;
       minianOrbitRadius = planetOrbitRadius * 0.45;
     }
 
     function update(time, delta) {
-      // Advance or rewind simulation time.
       if (isPlaying) {
-          simulationTime += (delta * simulationSpeed) / 1000;
+        simulationTime += (delta * simulationSpeed) / 1000;
       } else if (isRewinding) {
-          simulationTime -= (delta * simulationSpeed) / 1000;
+        simulationTime -= (delta * simulationSpeed) / 1000;
       }
 
-      const centerX = game.scale.width / 2;
-      const centerY = game.scale.height / 2;
-
       globalGraphics.clear();
 
       // Draw the central star.
       globalGraphics.fillStyle(0xFFFF00, 1);
-      globalGraphics.fillCircle(centerX, centerY, 20);
+      globalGraphics.fillCircle(starX, starY, 20);
 
-      // Draw the planet's elliptical orbital path around the star.
+      // Draw planet's elliptical orbit.
       const bPlanet = planetOrbitRadius * Math.sqrt(1 - planetEcc * planetEcc);
       globalGraphics.lineStyle(1, 0x555555, 1);
-      globalGraphics.strokeEllipse(centerX, centerY, 2 * planetOrbitRadius, 2 * bPlanet);
+      globalGraphics.strokeEllipse(starX, starY, 2 * planetOrbitRadius, 2 * bPlanet);
 
-      // Get planet's position on its elliptical orbit.
+      // Compute planet's position.
       const planetPos = getEllipticalPosition(simulationTime, planetPeriod, planetOrbitRadius, planetEcc);
-      const planetX = centerX + planetPos.x;
-      const planetY = centerY + planetPos.y;
+      const planetX = starX + planetPos.x;
+      const planetY = starY + planetPos.y;
 
-      // Update planet container position.
       planetContainer.x = planetX;
       planetContainer.y = planetY;
-      // Planet rotates about its own axis with a 1-day period.
-      const planetRotationAngle = Phaser.Math.DegToRad((360 * (simulationTime % planetRotationPeriod)) / planetRotationPeriod);
+      const planetRotationAngle = Phaser.Math.DegToRad(360 * (simulationTime % planetRotationPeriod) / planetRotationPeriod);
       planetContainer.rotation = planetRotationAngle;
+      const subsolarAnglePlanet = Phaser.Math.Angle.Between(planetX, planetY, starX, starY);
+      planetContainer.nightOverlay.rotation = subsolarAnglePlanet + Math.PI/2 - planetContainer.rotation;
 
-      // Update night overlay so that the dark half covers the hemisphere away from the star.
-      const subsolarAngle = Phaser.Math.Angle.Between(planetX, planetY, centerX, centerY);
-      planetContainer.nightOverlay.rotation = subsolarAngle + Math.PI / 2 - planetContainer.rotation;
+      // Draw tilt indicator.
+      tiltIndicator.clear();
+      tiltIndicator.lineStyle(2, 0x00FFFF, 1);
+      const dx = (tiltLength/2) * Math.cos(tiltIndicatorAngle);
+      const dy = (tiltLength/2) * Math.sin(tiltIndicatorAngle);
+      tiltIndicator.strokeLineShape(new Phaser.Geom.Line(
+        planetX - dx, planetY - dy,
+        planetX + dx, planetY + dy
+      ));
 
-      // Draw moon orbital paths (elliptical) around Senthara.
-      // For each moon, compute semi-minor axis: b = a * sqrt(1 - ecc^2).
-      const bKeriel = kerielOrbitRadius * Math.sqrt(1 - kerielEcc * kerielEcc);
-      const bArkaen = arkaenOrbitRadius * Math.sqrt(1 - arkaenEcc * arkaenEcc);
-      const bMinian = minianOrbitRadius * Math.sqrt(1 - minianEcc * minianEcc);
-      globalGraphics.lineStyle(1, 0x888888, 1);
-      globalGraphics.strokeEllipse(planetX, planetY, 2 * kerielOrbitRadius, 2 * bKeriel);
-      globalGraphics.strokeEllipse(planetX, planetY, 2 * arkaenOrbitRadius, 2 * bArkaen);
-      globalGraphics.strokeEllipse(planetX, planetY, 2 * minianOrbitRadius, 2 * bMinian);
+      // Draw moon orbits around the planet.
+      drawMoonOrbit(planetX, planetY, kerielOrbitRadius, kerielEcc, 0x888888);
+      drawMoonOrbit(planetX, planetY, arkaenOrbitRadius, arkaenEcc, 0x888888);
+      drawMoonOrbit(planetX, planetY, minianOrbitRadius, minianEcc, 0x888888);
 
-      // Calculate and update moon positions relative to Senthara.
+      // Update each moon.
+      updateMoon(kerielContainer, kerielOrbitRadius, kerielEcc, kerielPeriod);
+      updateMoon(arkaenContainer, arkaenOrbitRadius, arkaenEcc, arkaenPeriod);
+      updateMoon(minianContainer, minianOrbitRadius, minianEcc, minianPeriod);
+
+      // Build astronomical header text.
+      const astroInfo = buildAstronomicalText(planetX, planetY);
+      astroText.setText(astroInfo);
+    }
+
+    // Draw elliptical orbit centered at (px,py) with semi-major axis a and eccentricity ecc.
+    function drawMoonOrbit(px, py, a, ecc, color) {
+      const b = a * Math.sqrt(1 - ecc * ecc);
+      globalGraphics.lineStyle(1, color, 1);
+      globalGraphics.strokeEllipse(px, py, 2 * a, 2 * b);
+    }
+
+    // Update a moon's position, tidal locking, and its night overlay.
+    function updateMoon(moonContainer, a, ecc, period) {
+      const pos = getEllipticalPosition(simulationTime, period, a, ecc);
+      const moonX = planetContainer.x + pos.x;
+      const moonY = planetContainer.y + pos.y;
+      moonContainer.x = moonX;
+      moonContainer.y = moonY;
+      moonContainer.rotation = Phaser.Math.Angle.Between(moonX, moonY, planetContainer.x, planetContainer.y);
+      const overlay = moonContainer.list[moonContainer.list.length - 1];
+      const subsolarAngleMoon = Phaser.Math.Angle.Between(moonX, moonY, starX, starY);
+      overlay.rotation = subsolarAngleMoon + Math.PI/2 - moonContainer.rotation;
+    }
+
+    // Build the astronomical header text.
+    function buildAstronomicalText(planetX, planetY) {
+      let info = "Senthara\n";
+      info += "Date: " + getSentharaDate(simulationTime) + "\n";
+
+      // For each moon, compute its lit fraction and determine waxing/waning.
       // Keriel:
-      const kerielPos = getEllipticalPosition(simulationTime, kerielPeriod, kerielOrbitRadius, kerielEcc);
-      const kerielX = planetX + kerielPos.x;
-      const kerielY = planetY + kerielPos.y;
-      kerielContainer.x = kerielX;
-      kerielContainer.y = kerielY;
-      kerielContainer.rotation = Phaser.Math.Angle.Between(kerielX, kerielY, planetX, planetY);
+      const kerielX = kerielContainer.x;
+      const kerielY = kerielContainer.y;
+      let fracKeriel = getMoonLitFraction(kerielX, kerielY, starX, starY, planetX, planetY);
+      let waxingKeriel = (fracKeriel >= oldFracKeriel);
+      let emojiKeriel = getMoonPhaseEmoji(fracKeriel, waxingKeriel);
+      let kerielDay = Math.floor(simulationTime % kerielPeriod) + 1;
+      oldFracKeriel = fracKeriel;
+
+      info += `Keriel Day: ${kerielDay}  (Illum=${(fracKeriel * 100).toFixed(0)}% ${emojiKeriel})\n`;
 
       // Arkaen:
-      const arkaenPos = getEllipticalPosition(simulationTime, arkaenPeriod, arkaenOrbitRadius, arkaenEcc);
-      const arkaenX = planetX + arkaenPos.x;
-      const arkaenY = planetY + arkaenPos.y;
-      arkaenContainer.x = arkaenX;
-      arkaenContainer.y = arkaenY;
-      arkaenContainer.rotation = Phaser.Math.Angle.Between(arkaenX, arkaenY, planetX, planetY);
+      const arkaenX = arkaenContainer.x;
+      const arkaenY = arkaenContainer.y;
+      let fracArkaen = getMoonLitFraction(arkaenX, arkaenY, starX, starY, planetX, planetY);
+      let waxingArkaen = (fracArkaen >= oldFracArkaen);
+      let emojiArkaen = getMoonPhaseEmoji(fracArkaen, waxingArkaen);
+      let arkaenDay = Math.floor(simulationTime % arkaenPeriod) + 1;
+      oldFracArkaen = fracArkaen;
+
+      info += `Arkaen Day: ${arkaenDay}  (Illum=${(fracArkaen * 100).toFixed(0)}% ${emojiArkaen})\n`;
 
       // Minian:
-      const minianPos = getEllipticalPosition(simulationTime, minianPeriod, minianOrbitRadius, minianEcc);
-      const minianX = planetX + minianPos.x;
-      const minianY = planetY + minianPos.y;
-      minianContainer.x = minianX;
-      minianContainer.y = minianY;
-      minianContainer.rotation = Phaser.Math.Angle.Between(minianX, minianY, planetX, planetY);
+      const minianX = minianContainer.x;
+      const minianY = minianContainer.y;
+      let fracMinian = getMoonLitFraction(minianX, minianY, starX, starY, planetX, planetY);
+      let waxingMinian = (fracMinian >= oldFracMinian);
+      let emojiMinian = getMoonPhaseEmoji(fracMinian, waxingMinian);
+      let minianDay = Math.floor(simulationTime % minianPeriod) + 1;
+      oldFracMinian = fracMinian;
 
-      // Update the Senthara calendar date text.
-      dateText.setText(getSentharaDate(simulationTime));
+      info += `Minian Day: ${minianDay}  (Illum=${(fracMinian * 100).toFixed(0)}% ${emojiMinian})\n`;
+
+      // Cycle progress.
+      let shortProg = Math.floor(simulationTime % shortCycleLen);
+      let longProg  = Math.floor(simulationTime % longCycleLen);
+      info += `Short Cycle: ${shortProg} / ${shortCycleLen} days (~274 years)\n`;
+      info += `Long Cycle:  ${longProg} / ${longCycleLen} days (~6027 years)`;
+      return info;
     }
   </script>
 </body>
