## DON'T Run THIS!!!!
from astropy.coordinates import SkyCoord
old_colnames = ['ummed', 'gmmed', 'rmmed', 'immed', 'zmmed', 'umsig', 'gmsig', 'rmsig', 'imsig', 'zmsig']
colnames = ['umag', 'gmag', 'rmag', 'imag', 'zmag', 'uErr', 'gErr', 'rErr', 'iErr', 'zErr']
col_dict=dict(zip(old_colnames, colnames))
col_dict
s82=s82.map_partitions(lambda df: df.rename(columns=col_dict))
s82=s82.map_partitions(lambda df: df.assign(Mr=-99, FeH=-99, MrEst=-99,
MrEstUnc=-99, FeHEst=-99))
s82=s82.map_partitions(lambda df: df.assign(ug=df.umag-df.gmag))
s82=s82.map_partitions(lambda df: df.assign(gr=df.gmag-df.rmag))
s82=s82.map_partitions(lambda df: df.assign(gi=df.gmag-df.imag))
s82=s82.map_partitions(lambda df: df.assign(ri=df.rmag-df.imag))
s82=s82.map_partitions(lambda df: df.assign(iz=df.imag-df.zmag))
s82=s82.map_partitions(lambda df: df.assign(ugErr=np.sqrt(df.uErr**2+df.gErr**2)))
s82=s82.map_partitions(lambda df: df.assign(grErr=np.sqrt(df.gErr**2+df.rErr**2)))
s82=s82.map_partitions(lambda df: df.assign(giErr=np.sqrt(df.gErr**2+df.iErr**2)))
s82=s82.map_partitions(lambda df: df.assign(riErr=np.sqrt(df.rErr**2+df.iErr**2)))
s82=s82.map_partitions(lambda df: df.assign(izErr=np.sqrt(df.iErr**2+df.zErr**2)))
s82=s82.map_partitions(lambda df: df.assign(glon=SkyCoord(df.ra, df.dec, unit="deg").galactic.l.deg))
s82=s82.map_partitions(lambda df: df.assign(glat=SkyCoord(df.ra, df.dec, unit="deg").galactic.b.deg))
gi_cut = (s82['gi'] > 0.2) & (s82['gi'] < 3)
s82 = s82[gi_cut]