zerocombine input="*.Zero*.fits" output="Zero" combine="average" reject="minmax" \
ccdtype=" " process- delete- scale="none" statsec="" nlow=0 nhigh=1 \
nkeep=1 mclip+ lsigma=3. hsigma=3. rdnoise="RDNOISE" gain="GAIN" \
snoise="0." pclip=-0.5 blank=1.