Clarify that vega needs to be installed for server
@@ -89,6 +89,12 @@ To install the notebook and Altair with pip, run the following command::
$ pip install -U altair vega_datasets notebook vega
+.. note::
+
+ If you have multiple Python environments, the vega_ package must be
+ installed in the Python environment that runs ipykernel *as well as*
+ the Python environment that runs the Jupyter Notebook server.
+
Once the packages and extensions are installed, launch the notebook by running::
$ jupyter notebook
