function selection(tgt) {
const isSouth = (tgt.TARGET_RA < 85) || (tgt.TARGET_RA > 300);
return (tgt.GMAG - tgt.RMAG > options.GRmin) &&
(tgt.ZMAG < options.ZMAGmax) &&
options.ttypes.includes(tgt.TARGET_TYPE) && (
(options.region == "All") ||
((options.region == "South") && isSouth) ||
((options.region == "North") && !isSouth));
}