Well, the draft starts at 11 am ET, and if the 24 teams picking in front of us take the maximum 15 minutes, it comes out to a total of 360 minutes which is 6 hours. That means the latest possible time is around 5:00 ET. However, it should be a little bit earlier than that, as teams don't always use up the full 15 minutes.
It starts at noon...ESPN keeps saying the coverage starts at 11, but that's just it: the coverage. So the latest possible time is 6:00 ET.
When the moon blocks out the sun, and the earth is covered in shadows, then you will know that it is the time of the apocalypse, and that it's time for the Jets to make their first selection in the draft.