Allow refreshing tile cache.

frontend/package.json

@@ -5,7 +5,7 @@
   },
   "dependencies": {
     "@jupyter-widgets/base": "^2  || ^3 || ^4 || ^5 || ^6",
-    "@wwtelescope/research-app": "^0.16.0",
+    "@wwtelescope/research-app": "^0.17.0",
     "underscore": "^1"
   },
   "description": "WorldWide Telescope from Python",

pywwt/core.py

@@ -1372,3 +1372,13 @@ class BaseWWTWidget(HasTraits):
 
     def _save_added_data(self, dir):
         self.layers._save_all_data_for_serialization(dir)
+
+    # Miscellaneous
+
+    def refresh_tile_cache(self):
+        """
+        Clear the current cache of tiles.
+        Note that this should only be used when necessary, as any
+        previously downloaded tiles will need to be re-fetched.
+        """
+        self._send_msg(event="clear_tile_cache")