In Daniel 7, we learn after the one coming on the clouds like the son of man during the 4th beast, there is the last beast who is said to have subdued 3 horns and a little horn comes up and has a time, two times and half a time but then will be annihilated and forever destroyed.

This time period is also given to Daniel in chapter 12:7 to the end of all the things Daniel has seen in chapter 11. Daniel is told in Dan 12:11 another time period of 1,290 days followed by 45 more days to 1,335 days.

This time period is referring to Daniel 11:33 not the period of the end.

Jesus refers to this time period as something his hearers should be looking for (not Antiochus)!

Matthew 24: 15-20
15 "Therefore when you see the abomination of desolation which was spoken of through Daniel the prophet, standing in the holy place (let the reader understand),
16 then let those who are in Judea flee to the mountains;
17 let him who is on the housetop not go down to get the things out that are in his house;
18 and let him who is in the field not turn back to get his cloak.
19 "But woe to those who are with child and to those who nurse babes in those days!
20 "But pray that your flight may not be in the winter, or on a Sabbath;

Also the same language in Luke’s gospel:

Luke 21:20-22
20 "But when you see Jerusalem surrounded by armies, then recognize that her desolation is at hand.
21 "Then let those who are in Judea flee to the mountains, and let those who are in the midst of the city depart, and let not those who are in the country enter the city;
22 because these are days of vengeance, in order that all things which are written may be fulfilled.

So, this is before Jesus goes to the cross he begins saying these things. The abomination that causes desolation is referring to the temple being desolate:

Matthew 23: 38 "Behold, your house is being left to you desolate!

The 1,290 days refers to the ministry, death and resurrection of Jesus (he who became sin for us --- an abomination to God) is what made the temple desolate.

There are 49 days from Passover to Pentecost. If you subtract the 3 days in the tomb and add 46 days to 1,290 you get 1,336 days. However they were in the upper room a day before (on day 1,335). Jesus ascended on day 1,330 (1,290 + 40 days). In Acts 2:1 the Greek says Pentecost was approaching (as the only other time you see this form is in Luke’s gospel (same author) when he says Jesus’ day was approaching (Luke 9:51).

They would have been in temple had it been the day of Pentecost. They were all in the upper room when the Holy Spirit descended in tongues of fire.

Daniel 12:12 "How blessed is he who keeps waiting and attains to the 1,335 days!