What is the exact time on Minecraft that is sunrise?

The Minecraft day is 20 (real-life) minutes long, which translates into 24000 game ticks (there are 20 ticks per second).

Sunrise is implemented as the last part of the day-night cycle and is 90 seconds (1800) ticks) long (according to the wiki), starting at around game time 22200

when the sky will look like this (facing due east)

to game time 0 when the sky will look like this (also facing due east)

The easiest way to detect sunrise is to use the daylight sensor that has been introduced in the snapshots in combination with a comparator

22796 is the soonest a directly exposed daylight sensor powers on in the morning.