Merge pull request #868 from punch-mission/whats-up-doc

Minor documentation update for data

Author: jmbhughes

changelog/868.doc.rst

@@ -0,0 +1 @@
+Minor documentation update for data, to clarify new data version, and data physical units.

docs/data/index.rst

@@ -3,13 +3,15 @@ Data
 
 Welcome to PUNCH data!
 
-Our latest version of data is 0j (learn more about `data versions <data_versions.html>`_).
+Our latest version of data is 0k (learn more about `data versions <data_versions.html>`_).
 We will begin providing browse data and movies soon.
 
 PUNCH is still being calibrated, but you can take a look at the most up to date data
 through the `Get Data <https://punch.space.swri.edu/punch_science_getdata.php>`_ page on our PUNCH website.
 The most commonly used data products are L3_PAM (polarized) and L3_CAM (clear) low-noise mosaics.
 
+Note that from data level 1 and onward, all data is represented in units of Mean Solar Brightness (MSB).
+
 For more information about how to download data, see this `data access <access.html>`_ page.
 
 For more information about data analysis tools, see the `example gallery <../auto_examples/index.html>`_.