This directory is purposely empty in the GitHub repository except for
this README file.  The atmospheric model grids used for the PypeIt
telluric corrections are very large and SHOULD NOT BE CHECKED IN to
PypeIt; see the .gitignore file.

Downloading and installation of the relevant files from a shared Google
Drive directory is explained by the PypeIt installation documentation here:

https://pypeit.readthedocs.io/en/latest/installing.html#atmospheric-model-grids

See also a description of the telluric correction procedure and script
here:

https://pypeit.readthedocs.io/en/latest/telluric.html

