Daniel’s 1,290 days
Daniel said the saints would be dominated by a little horn, that arises among the 10 horns of a terrible looking beast, representing the Roman Empire. The horn endures for a period of time called “a time, times and a half.” This little horn has “eyes like the eyes of a man, and a mouth speaking great things.” Daniel wrote of the little horn,
And he shall speak great words against the most High, and shall wear out the saints of the most High, and think to change times and laws: and they shall be given into his hand until a time and times and the dividing of time.
“Eyes like the eyes of a man” seem to represent a human viewpoint, as opposed to a divine one.
In chapter 12, the period that Daniel called “a time, times and a half” is shown to extend to the end of the age. Within that period, the saints would become scattered, and this has been fulfilled, as today they are scattered among tens of thousands of denominations and sects. Daniel wrote:
And I heard the man clothed in linen, which was upon the waters of the river, when he held up his right hand and his left hand unto heaven, and sware by him that liveth for ever that it shall be for a time, times, and an half; and when he shall have accomplished to scatter the power of the holy people, all these things shall be finished.
Further information about the “time, times, and an half” was given in verses 11 & 12.
And from the time that the daily sacrifice shall be taken away, and the abomination that maketh desolate set up, there shall be a thousand two hundred and ninety days.
The “daily sacrifice” being abolished seems to refer to the Jewish temple ritual sacrifices, that ended when the Jerusalem temple was destroyed by the Romans in 70 AD. Once the earthly temple was gone, the only holy place remaining, where an abomination could be set up, was the church! And John said the antichrist spirit was already present, which is how we know it is the last time.
1 John 2:18
Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
Blessed is he that waiteth, and cometh to the thousand three hundred and five and thirty days.
Compare these two numbers, 1,335 days, and 1,290 days. They are both symbolic, and represent the remaining time of the church. The whole time of the church, from the ascension of Jesus to the end of the age, is represented by the larger number, the 1,335 days. Jesus is the one who waits in heaven until it is fulfilled. The 1,290 days represents a part of the church age. It began after the 1,335 days.
It was after 70 AD, when most of the apostles had died, that the abomination that makes desolate, the antichrist spirit, was set up and gained influence in the church. But the apostle John remained alive, and he reported it. The 1,290 days represents the time remaining after the antichrist spirit became established, late in the first century.
When John wrote the Apocalypse, he used an even smaller number, 1,260 days, to represent the remaining time of the church. He wrote after the destruction of the temple, probably about 95 AD, and he recognized that the antichrist spirit was already present. The 1,290 days is intermediate between 1,335 days and 1,260 days. That period began before John wrote the Apocalypse. The beginnings of the antichrist spirit was established within the church, and there is evidence of it in the warning messages given to the seven churches. By the events that Daniel associated with the 1,290 days, we can understand what the abomination of desolation represents. It is the spirit of antichrist, that John said was already present in the world. [1 John 4:3]
Patrick Fairbairn, referring to the prophecies about an abomination of desolation, suggested that there is “a profound spiritual meaning in the prophecy, such as thoughtful and serious minds alone could apprehend.” He wrote: 
ABOMINATION OF DESOLATION. This striking and somewhat enigmatical expression occurs properly but once in the English Bible; namely, in the address delivered by our Lord to his disciples respecting the destruction of Jerusalem and the last days, Mat. xxiv. 15; Mar. xiii. 11. But as there introduced it is given as a quotation from the prophet Daniel–“When ye shall see the abomination of desolation spoken of by Daniel the prophet, stand in the holy place, whoso readeth, let him understand”–although when we turn to Daniel the precise expression is not found in the English Bible. This arises from the translation of the Septuagint being adopted by our Lord (*** *** ***), the exact equivalent to which in English is “abomination of desolation,” while the original in Hebrew slightly differs. The passage actually referred to is Da. ix. 27, where our translators render “for the overspreading of abominations he shall make it desolate.” This, however, is not the most accurate rendering; it should rather be “over top of abominations (will be) the desolator,” or destroyer. And so again in two other passages, which are generally understood to point to the Maccabean times- “And they shall place (or set up) the abomination, the desolator,” ch. xi. 31, and “till the abomination that desolates,” ch. xii. 11. The chief difference among commentators, as to the meaning of the expression, has respect to the point, whether the abomination, which somehow should carry along with it the curse of desolation, ought to be understood of the idolatrous and corrupt practices which should inevitably draw down desolating inflictions of vengeance, or of the heathen powers and weapons of war that should be the immediate instruments of executing them. There appear to be conclusive reasons for understanding the expression of the former. 1. By far the most common use of the term abomination or abominations, when referring to spiritual things, and especially to things involving severe judgments and sweeping desolation, is in respect to idolatrous, and other foul corruptions. It was the pollution of the first temple, or the worship connected with it by such things, which in a whole series of passages is described as the abominations that provoked God to lay it in ruins, 2 Ki. xxi 2-13; Je. vii. 10-14; Eze. v. 11; vii. 8,9,20-23. And our Lord very distinctly intimated, by referring on another occasion to some of these passages, that as the same wickedness substantially was lifting itself up anew, the same retributions of evil might certainly be expected to chastise them, Mat. xxi. 13. 2. When reference is made to the prophecy in Daniel it is coupled with a word, “Whoso readeth let him understand,” which seems evidently to point to a profound spiritual meaning in the prophecy, such as thoughtful and serious minds alone could apprehend. But this could only be the case if abominations in the moral sense were meant; for the defiling and desolating effect of heathen armies planting themselves in the holy place was what a child might perceive. Such dreadful and unseemly intruders were but the outward signs of the real abominations, which cried for vengeance in the ear of heaven. The compassing of Jerusalem with armies, therefore, mentioned in Lu. xxi. 20, ready to bring the desolation, is not to be regarded as the same with the abomination of desolation; it indicated a further stage of matters. 3. The abominations which were the cause of the desolations are ever spoken of as springing up from within, among the covenant people themselves, not as invasions from without. They are so represented in Daniel also, ch. xi. 30,32; xii. 9,10; and that the Jews themselves, the better sort of them at least, so understood the matter, is plain from 1 Mac. i. 54-57, where, with reference to the two passages of Daniel just noticed, the heathen-inclined party in Israel are represented, in the time of Antiochus, as the real persona who “set up the abomination of desolation and built idol altars;” comp. also 2 Mac. iv. 15-17. (See on the whole subject, Hengstenberg on the Genuineness of Daniel, ch. iii. § 3; and Christology, at Da. ix. 27, with the authorities there referred to.)
1. Patrick Fairbairn, ed. The Imperial Bible Dictionary. Blackie and Son, 1866. p. 10.