Update nrc_utils.py
Update nrc_utils.py

def coron_detector(mask, module, channel=None)
Returns detector name for a given coronagraphic mask, module, and channel.

Update Stellar types to https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt

JarronL/pynrc