As far as I know,dusk is the beginning of darkness in the evening. But it is often confused with sunset,which is the daily disappearance of the sun below the horizon. The sky generally remains bright and blue for some time after the sun sets. This period is known as twilight. Dusk is the end of the evening twilight.Somebody like the dawn,others like dusk.I prefer dusk,as the beauty is represents the fulfillment of one day's work.Sometimes dusk analogies the old ,I think it is the praise for the old,for their devotion.
I don't know what time dusk is. I don't know why people don't just use actual time instead of using dusk!!!