Hello Jan...

With all do respect, your actually wrong about this. The 1290 days are the time period between the two events. The constant feature is removed, and then 1290 days later the disgusting thing is placed. Read it again, that is the purpose of the 1290 days, it's to tell you the time period in between.

We must use the first century fulfillment to determine its final fulfillment in the time of the end;

Eleazar ben Hanania was governor of the temple in the year 66CE at the temple in Jerusalem. He caused the sacrifices to the Roman emperor and people to cease which ignited the Jewish war. 1290 days later Rome entered the temple to destroy it.

This is why we read in such places like Joel 1 that sacrifices cease first then later Gods people are attacked. Or Amos where Gods people go into captivity then after being restored to him they are attacked sparking Armageddon. Gen 11:2 "But as for the courtyard that is outside the temple sanctuary, leave it out and do not measure it, because it has been given to the nations, and they will trample the holy city underfoot for 42 months." The first event is not the placing of the disgusting thing, Jerusalem will be circled first for 42 months while Jehovah's people are dressed in sackcloth, after which point they will no longer be in sackcloth for their Lord will be enthroned. Then 30 days later the disgusting thing will be placed, meaning the world will come against the restored temple of God on earth, Christs brothers remaining, to kill them physically.

Constant feature=Watchtower magazine presenting Jehovah's kingdom to the world.
Disgusting thing=8th kings attempt to cut their bands from Jehovah, sparking Armageddon.

 

We do not have the exact days in history in our modern day, but many sites talk about the months in which each event occurs, and the months match the days between these two events. Besides the prophecy is written to Christs brothers and will have it's greatest fulfillment in the time of the end and we will know exactly how many days between events for Jehovah has kindly gave them to us in scripture.

Although there were many in the first century that knew the destruction was coming. One would have known the sacrifices were ceased in 66CE and only needed to read Daniel to know that Rome would enter the temple 1290 days later.

One such person looking forward to Jerusalem's destruction was Jesus ben Ananias, if your not familiar with him feel free to look him up...