diff --git a/package.json b/package.json
index b0e6abc..404d239 100644
--- a/package.json
+++ b/package.json
@@ -57,6 +57,11 @@
       "require": "./dist/astrometry.cjs",
       "types": "./dist/astrometry.d.ts"
     },
+    "./calendar": {
+      "import": "./dist/calendar.js",
+      "require": "./dist/calendar.cjs",
+      "types": "./dist/calendar.d.ts"
+    },
     "./common": {
       "import": "./dist/common.js",
       "require": "./dist/common.cjs",
diff --git a/src/index.ts b/src/index.ts
index 2a09626..1da5bba 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -39,6 +39,10 @@ export {
 
 /*****************************************************************************************************************/
 
+export type { GregorianMonth } from './calendar'
+
+/*****************************************************************************************************************/
+
 export {
   type CartesianCoordinate,
   type EclipticCoordinate,
diff --git a/vite.config.ts b/vite.config.ts
index 3075dbf..29fafa5 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -22,6 +22,7 @@ const modules = [
   'aberration',
   'apparent',
   'astrometry',
+  'calendar',
   'common',
   'conjunction',
   'constants',