mongoose select nested

var fields = { 'properties.OBJECTID': 1, 'properties.TIMESTAMP': 1 };
var query = Feature.find({id: 1}).select(fields);

 System.findOne({ 'nodes.main.Alpha': 23000}, function(err, system){
   if(err){console.log(err);}
   else{console.log(system);}
 });