So, where are you getting 1844?
Year 1844, comes from Biblical verses, in many ways. One of them is the 2300 Days Prophecy of Daniel 8.
Tony Bristow-Stagg, provided the verse for that one with a link. Here is also a much better detail explanation in the Baha'i Scriptures:
In the eighth chapter of the Book of Daniel, verse thirteen, it is said: “Then I heard one saint speaking, and another saint said unto that certain saint which spake, How long shall be the vision concerning the daily sacrifice, and the transgression of desolation, to give both the sanctuary 42 and the host to be trodden under foot?” Then he answered (v. 14): “Unto two thousand and three hundred days; then shall the sanctuary be cleansed”; (v. 17) “But he said unto me … at the time of the end shall be the vision.” That is to say, how long will this misfortune, this ruin, this abasement and degradation last? meaning, when will be the dawn of the Manifestation? Then he answered, “Two thousand and three hundred days; then shall the sanctuary be cleansed.” Briefly, the purport of this passage is that he appoints two thousand three hundred years, for in the text of the Bible each day is a year. Then from the date of the issuing of the edict of Artaxerxes to rebuild Jerusalem until the day of the birth of Christ there are 456 years, and from the birth of Christ until the day of the manifestation of the Báb there are 1844 years. When you add 456 years to this number it makes 2300 years. That is to say, the fulfillment of the vision of Daniel took place in the year A.D. 1844, and this is the year of the Báb’s manifestation according to the actual text of the Book of Daniel. Consider how clearly he determines the year of manifestation; there could be no clearer prophecy for a manifestation than this.
In Matthew, chapter 24, verse 3, Christ clearly says that what Daniel meant by this prophecy was the date of the manifestation, and this is the verse: “As He sat upon the mount of Olives, the disciples came unto Him privately, saying, Tell us, when shall these things be? and what shall be the sign of Thy coming, and of the end of the world?” One of the explanations He gave them in reply was this (v. 15): “When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand).” In this answer He referred them to the eighth chapter of the Book of Daniel, saying that everyone who reads it will understand that it is this time that is spoken of. Consider how clearly the manifestation of the Báb is spoken of in the Old Testament and in the Gospel.
Is it an educated guess, just a shot in the dark, are you trying to read something into the text that may or may not be actually there?
It is not an educated guess. It is calculation, which comes to year 1844.
Are you confident about 1844? If so, what evidence makes you so confident?
Absolutely confident. Because in the year 1844, many events happened which are compatible with Biblical Prophecies, in a sense that, the verses of Bible and History become parallel. I can also show other verses from Bible, which point to the same year, with other Prophecies historically fulfilled which can be verified with Historical Evidences.
Here are some of those events:
“I was given a reed like a measuring rod and was told, "Go and measure the temple of God and the altar, with its worshipers. But exclude the outer court do not measure it, because it has been given to the Gentiles. They will trample on the holy city for 42 months”.
Revelation 11:1-2
So, according to this prophecy, the holy city, which is Jerusalem will be given to Gentiles according to the Will of God. The Gentiles are basically the non Jews, according to many Bible scholars.
Now there is also a match in the history for this.
From Wikipedia:
“The Islamization of Jerusalem began in the first year A.H. (623 CE), when Muslims were instructed to face the city while performing their daily prostrations and, according to Muslim religious tradition, Muhammad's night journey and ascension to heaven took place”
Jerusalem - Wikipedia
So, the first year in Islamic Calendar is a beginning of period that the Holy city was given to Arabs in a Religious Sense.
But for how long was it given to them? The Bible says 42 months.
Lets see if history and religion can match here.
42 months is 1260 days, and in Bible, each day of Lord is 1 year.
That would be 1260 years.
When you count 1260 lunar years, beginning year 623 CE, it comes to the year 1844. Now this is the year that the Bab declared a new Revelation, thus, the Holy City which was given to Islam, was taken from them, in a sense that, Islam was abrogated. In year 1844 also an edict was signed, which initiated the process of return of the Jews.
From Wikipedia , the return was initiated in year 1844, when the Ottoman Empire signed an edict of tolerance which:
“….infers religious tolerance through ending executions for apostasy for Jews that seemed to convert making their social situation easier while actually keeping their personal and group identity in their Judaic religion. Jerusalem has had the largest Jewish population in Palestine in recent centuries since about 1844…”
Edict of Toleration 1844 - Wikipedia
Now, return of Jews to Holy Land was also prophesied in Bible in this manner:
"This is what the LORD Almighty, the God of Israel, says: "When I bring them back from captivity, the people in the land of Judah and in its towns will once again use these words: 'The LORD bless you, you prosperous city, you sacred mountain…..The days are coming," declares the LORD, "when I will make a new covenant with the people of Israel and with the people of Judah.” Jerm. 31:23-31
What is noteworthy is that according to this Prophecy, return of Jews would happen at a time God makes a new covenant, and from Baha'i point of view, Revelation of the Bab was a new Covenant revealed in 1844, the year that edict was signed and Jews begin to return.
The Life of the Báb | What Bahá’ís Believe