11 From the time that the continual offering shall be taken away, and the abomination that makes desolate set up, there shall be one thousand two hundred ninety days.
from the time the daily sacrifice is taken away and the abomination of desolation is set up – as we discussed at Dan 8:11-13, this refers to the departure of the holy spirit and the efficacy of baptism to wash away sins.
1290 days – the Angel swore it would be for time, times and half a time. In terms of months, this is closest to 43 months on the Jewish calendar (every three years has a leap year that adds one month); and multiplied by 30, we get to 1290 days. In the Book of Revelation, the months been simply rounded as 12 + 24 + 6 = 42 months, and 42 X 30 = 1260 days.