This directory contains the MARCS models used to create the APOGEE synthetic 
spectral grids.
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These atmospheres were largely created by B. Edvarsson for the SDSS/APOGEE project,
and differ from the normal MARCS grids in that they provide regularly spaced
rectangular grids in Teff, log g, [M/H], [alpha/M], and [C/M]. See 
Readme_MARCS_v3_2016.txt
These grids were supplemented by models for logg=5.5 created by Thomas Masseron.
<p>
The MARCS models can be found in directories mod_*, organized by [M/H].
<p>
The nltepop directory contains the atmospheres formatted for use with Synspec,
including NLTE level population calculations by Yeisson Osorio.