diff --git a/packages/telescope-embedly/lib/embedly.js b/packages/telescope-embedly/lib/embedly.js
index a195f6582..4b00c01b1 100644
--- a/packages/telescope-embedly/lib/embedly.js
+++ b/packages/telescope-embedly/lib/embedly.js
@@ -69,8 +69,9 @@ var thumbnailHeightProperty = {
 }
 Settings.registerField(thumbnailHeightProperty);
 
-// add callback that adds "has-thumbnail" or "no-thumbnail" CSS classes
-Telescope.callbacks.register("postClass", function (post, postClass){
+function addThumbnailClass (post, postClass){
   var thumbnailClass = !!post.thumbnailUrl ? "has-thumbnail" : "no-thumbnail";
   return postClass + " " + thumbnailClass;
-});
+}
+// add callback that adds "has-thumbnail" or "no-thumbnail" CSS classes
+Telescope.callbacks.register("postClass", addThumbnailClass);
diff --git a/packages/telescope-tags/lib/categories.js b/packages/telescope-tags/lib/categories.js
index c4f833015..91a2be2ae 100644
--- a/packages/telescope-tags/lib/categories.js
+++ b/packages/telescope-tags/lib/categories.js
@@ -62,7 +62,8 @@ getCategoryUrl = function(slug){
 };
 
 // add callback that adds categories CSS classes
-Telescope.callbacks.register("postClass", function (post, postClass){
+function addCategoryClass (post, postClass){
   var classArray = _.map(getPostCategories(post), function (category){return "category-"+category.slug});
   return postClass + " " + classArray.join(' ');
-});
+}
+Telescope.callbacks.register("postClass", addCategoryClass);