Database
[{"Item":"Test1","millisecond":188760000},{"Item":"Test2","millisecond":23280000},{"Item":"Test3","millisecond":128820000},]
Query
db.collection.aggregate([{$set:{hours:{$concat:[{$toString:{$sum:[-24,{$multiply:[{$dayOfYear:{$toDate:{$toLong:"$millisecond"}}},24]},{$hour:{$toDate:{$toLong:"$millisecond"}}},]}},{$dateToString:{date:{$toDate:{$toLong:"$millisecond"}},format:":%M:%S"}}]}}}])