When exactly does the "totality phase" of tonight's total lunar eclipse actually begin?

The total phase, when the Moon slips completely into the dark umbral shadow cast by the Earth, will begin at 2:41 A.M. EST and last until 3:53 A.M. From 1:43 to 2:41 A.M. the dark shadow cast by the Earth will progress across the face of the Moon, while from 3:53 to 5:01 A.M. EST you will see the dark shadow gradually move off the face of the Moon.