diff --git a/apps/planetarium/README.md b/apps/planetarium/README.md
index 2e07794e9..ff2178888 100644
--- a/apps/planetarium/README.md
+++ b/apps/planetarium/README.md
@@ -1 +1,11 @@
-# Planetarium
\ No newline at end of file
+# Planetarium
+
+This planetarium takes your position and time and plots the sky as it is.
+
+No planets, or moon, only stars. It can show the 350 most brilliant stars in the sky. 
+
+Plan is to show also constellations, but this is work in progress. Now it shows Taurus and Orion as examples.
+
+I think code is quite optimized already. It runs as fast as I could make it run. If someone has some ideas to speed it up, I could plot more stars.
+
+Basic equations to compute declination and right ascension for stars where taken from this [github repo](https://github.com/Michi83/planetarium).
\ No newline at end of file
diff --git a/apps/planetarium/planetarium.app.js b/apps/planetarium/planetarium.app.js
index 11d1bbde3..1fc2615a7 100644
--- a/apps/planetarium/planetarium.app.js
+++ b/apps/planetarium/planetarium.app.js
@@ -62,7 +62,7 @@ function drawStars(lat,lon,date){
   var size = 240;
 
   storage = require('Storage');
-  f=storage.read("planetarium.csv","r");
+  f=storage.read("planetarium.data.csv","r");
   linestart=0;
   g.clear();