diff --git a/assets/js/app.js b/assets/js/app.js
index 76524a8..3d3c934 100644
--- a/assets/js/app.js
+++ b/assets/js/app.js
@@ -44,9 +44,9 @@ const html = htm.bind(h);
 
 // ── Scope time-lapse playback ───────────────────────────────────────────
 // Drives the big scope through the next 24h so you can watch the sky/ground
-// gradients and weather evolve. Speed: 15 simulated minutes every 5 real
-// seconds (≈ a full day in 8 minutes). UI advances smoothly every 200ms.
-const PLAYBACK_SIM_MS_PER_REAL_MS = 180;          // 15 min / 5 s = 180×
+// gradients and weather evolve. Speed: 15 simulated minutes every 1 real
+// second (≈ a full day in ~1.6 minutes). UI advances smoothly every 200ms.
+const PLAYBACK_SIM_MS_PER_REAL_MS = 900;          // 15 min / 1 s = 900×
 const PLAYBACK_STEP_MS            = 200;          // UI update cadence
 const PLAYBACK_WINDOW_MS          = 24 * 60 * 60 * 1000;