As part of it's 'Astro' program LAPD helicopters maintain an average nineteen-hours-per-day vigil over 'high crime areas', tactically coordinated to patrol car forces, and exceeding even the British Army's aerial surveillance of Belfast.
Just as good and virtue, sin and evil can only be given in vigil. Who sleeps, sleeps; for the asleep there is no sin, just as there is no good, nor virtue. There is only sleep. - Judas Iscariot The Flight of the Feathered Serpent
I receive Thee ransom of my soul. For love of Thee have I studied and kept vigil toiled preached and taught… - Thomas Aquinas