Fix dashboard startup regressions and mode utilities

routes/sstv.py

@@ -472,14 +472,14 @@ def stream_progress():
     return response
 
 
-def _get_timescale():
-    """Return a cached skyfield timescale (expensive to create)."""
-    global _timescale
-    with _timescale_lock:
-        if _timescale is None:
-            from skyfield.api import load
-            _timescale = load.timescale()
-        return _timescale
+def _get_timescale():
+    """Return a cached skyfield timescale (expensive to create)."""
+    global _timescale
+    with _timescale_lock:
+        if _timescale is None:
+            from skyfield.api import load
+            _timescale = load.timescale(builtin=True)
+        return _timescale
 
 
 @sstv_bp.route('/iss-schedule')