JW Insider

And, as discussed previously about Gerard Gertoux on the forum, the above link you provided gets into some of those exact details that show how the Neo-Babylonian chronology is "set in stone:"
In your link, Gertoux states:
The fall of the Assyrian empire, which took place in October 609 BCE after the battle of Harran, is characterized by a quadruple synchronisms, since the year of Assur-uballit II corresponds to year 17 of Nabopolassar to Josiah's year 31 and year 1 of Necho II.
According to the biography of Adad-Guppi12, mother of Nabonidus, Nabopolassar reigned 21 years, then Nebuchadnezzar 43 years, Amel-Marduk 2 years, Neriglissar 4 years just before Nabonidus. According to the Hillah's stele there were 54 years between the destruction of the temple of Sin, in Harran, and the beginning of the reign of Nabonidus. According to a Babylonian chronicle (BM 21901) and Adad-Guppi's stele, the temple of Harran was destroyed in the year 16 of Nabopolassar.
Dated lunar eclipses are: year 1 and 2 of Merodachbaladan (March 19/20 721 BCE, March 8/9 and September 1/2 720 BCE); year 5 of Nabopolassar (April 21/22 621 BCE); year 2 of !ama#-#uma-ukîn (April 10/11 666 BCE); year 42 of Nebuchadnezzar (March 2/3 562 BCE). A diary (VAT 4956) contains numerous astronomical conjunctions in years 37 and 38 of Nebuchadnezzar dated from astronomy in 568 and 567 BCE. An astronomical journal (BM 38462)17 list some lunar eclipses in the years 1 to 27 of Nebuchadnezzar which are dated from 604 to 578 BCE.
I think it was pretty brave of Gerard Gertoux to stand up against the WTS tradition publicly and show just why the accepted, evidenced chronology is so difficult to change and try to discredit.

Excellent point made here in the link you provided:
"The durations of the Babylonian reigns, from Eriba-Marduk (770-761) to Nabonidus (556-539), are all known. The chronology of these Babylonian kings is anchored on the dates set by the astronomy of five precisely described lunar eclipses."
Sometimes when we read about Babylonian or Mesopotamian chronology being revised, we think of the Neo-Babylonian period which, unfortunately for the WTS tradition, has been "set in stone" and therefore can't really be revised. 

There is NO Bible evidence for 539 BCE. There is NO Bible evidence for 587 BCE. There is NO Bible evidence for 607 BCE. I think most of us understand that by now. So, I propose a thread/topic where we shift the focus almost exclusively to the basic, fundamental question about the strength of the secular evidence in the Neo-Babylonian period. Why do we rely on it? Why does the WTS rely on secular Babylonian astronomer's evidence for Cyrus in 539? Why does the WTS reject the same evidence for Nebuchadnezzar's 18th year?  Is the evidence for Nebuchadnezzar's years actually 10 times better than for Cyrus?
When that question is solved, it also resolves the entire question about the 70 years, the WTS 20-year gap, the years of those kings that came just before and just after. And it will automatically link to the resolution of dates for events like the Fall of Nineveh, the Battle of Carchemish, the death of Josiah, the years of Zedekiah, the BCE dates for the three different exile events reported in Jeremiah 52. And , of course, it should answer the question about the complete lack of evidence for 607 as Nebuchadnezzar's 18th year.  
So in this new thread/topic there would need to be NO discussion of:
the 70 years of Jewish Exile, or the 70 years of Babylonian domination over other nations the purpose of the WTS 20-year gap 1914 Daniel 4, Gentile Times, the length of the 7 times/years, the length of the 2,520 days making up those 7 years Not even any discussion of Bible prophecies or references in: Jeremiah, 2 Chronicles, Isaiah, Zechariah, Daniel.  Just the years of Nebuchadnezzar's reign. Any discussion of other topics can be moved back to this topic/thread.

There is NO Bible evidence for 539 BCE. There is NO Bible evidence for 587 BCE. There is NO Bible evidence for 607 BCE. I think most of us understand that by now. So, I propose a thread/topic where we shift the focus almost exclusively to the basic, fundamental question about the strength of the secular evidence in the Neo-Babylonian period. Why do we rely on it? Why does the WTS rely on secular Babylonian astronomer's evidence for Cyrus in 539? Why does the WTS reject the same evidence for Nebuchadnezzar's 18th year?  Is the evidence for Nebuchadnezzar's years actually 10 times better than for Cyrus?
When that question is solved, it also resolves the entire question about the 70 years, the WTS 20-year gap, the years of those kings that came just before and just after. And it will automatically link to the resolution of dates for events like the Fall of Nineveh, the Battle of Carchemish, the death of Josiah, the years of Zedekiah, the BCE dates for the three different exile events reported in Jeremiah 52. And , of course, it should answer the question about the complete lack of evidence for 607 as Nebuchadnezzar's 18th year.  
So in this new thread/topic there would need to be NO discussion of:
the 70 years of Jewish Exile, or the 70 years of Babylonian domination over other nations the purpose of the WTS 20-year gap 1914 Daniel 4, Gentile Times, the length of the 7 times/years, the length of the 2,520 days making up those 7 years Not even any discussion of Bible prophecies or references in: Jeremiah, 2 Chronicles, Isaiah, Zechariah, Daniel.  Just the years of Nebuchadnezzar's reign. Any discussion of other topics can be moved back to this topic/thread.

The Bible mentions the specific reigns of certain foreign kings during the Judean Babylonian exile, and the post-exilic period. It mentions Nebuchadnezzar, Amel-Marduk, Belshazzar, Cyrus, etc. Mostly it mentions Nebuchadnezzar: his 1st year, his 2nd, his 7th, his 18th, his 19th, his 23rd, and the Bible also gives an indication that it must have been around his 43rd year when Amel-Marduk (Evil-Merodach) began to reign right after him. No other foreign king is mentioned in the Bible as much as Nebuchadnezzar.
So let's say we want to start putting actual BCE dates on the Neo-Babylonian kings. It looks like Nebuchadnezzar is a good place to start. To save space I will abbreviate his name as NEB and abbreviate his years of reign as NEB18 for his 18th year of reign, NEB7 for his 7th, etc. Other kings of the period will also be abbreviated like E-M for Evil-Merodach, NER for Neriglissar, NAB for Nabonidus, CYR for Cyrus etc.

I really like the fact that you are trying to work it out for yourself.
Because I was always so skeptical of the accepted, secular chronology I thought it was important to "start from scratch" and work the whole thing out for myself. 
I think most Witnesses don't realize that ANY time we see a B.C.E. date in the WTS publications, it means that we are relying on SECULAR chronology.
Personally, I'm convinced that the Bible is sufficient on its own to keep us fully equipped, therefore without any need to rely on secular chronology, so I give no special credence or reliance to any specific years with a BCE date attached to them. Doesn't mean they can't be helpful in trying to figure out the order of events, but even here, those secular dates aren't necessary in order to understand the Bible, and figure out the order of Biblical events. 
And from a purely Biblical perspective we aren't going to get any definite mentions of an eclipse or some other astronomical event that is tied to a specific month and day and year of a specific king. Therefore there can be no BCE dates calculated from the Bible. 
In my opinion, there are two main stumbling blocks that always hamper any chronology discussion, and they are related:
Witnesses are told that we are defending Biblical chronology based on a pivotal ('absolute') date of 539 BCE and the Biblical 70 years.  When arguing with Witnesses, Non-Witnesses don't (or won't) admit that the most logical and common-sense understanding of the 70 years favors the WTS viewpoint. 

And, as discussed previously about Gerard Gertoux on the forum, the above link you provided gets into some of those exact details that show how the Neo-Babylonian chronology is "set in stone:"
In your link, Gertoux states:
The fall of the Assyrian empire, which took place in October 609 BCE after the battle of Harran, is characterized by a quadruple synchronisms, since the year of Assur-uballit II corresponds to year 17 of Nabopolassar to Josiah's year 31 and year 1 of Necho II.
According to the biography of Adad-Guppi12, mother of Nabonidus, Nabopolassar reigned 21 years, then Nebuchadnezzar 43 years, Amel-Marduk 2 years, Neriglissar 4 years just before Nabonidus. According to the Hillah's stele there were 54 years between the destruction of the temple of Sin, in Harran, and the beginning of the reign of Nabonidus. According to a Babylonian chronicle (BM 21901) and Adad-Guppi's stele, the temple of Harran was destroyed in the year 16 of Nabopolassar.
Dated lunar eclipses are: year 1 and 2 of Merodachbaladan (March 19/20 721 BCE, March 8/9 and September 1/2 720 BCE); year 5 of Nabopolassar (April 21/22 621 BCE); year 2 of !ama#-#uma-ukîn (April 10/11 666 BCE); year 42 of Nebuchadnezzar (March 2/3 562 BCE). A diary (VAT 4956) contains numerous astronomical conjunctions in years 37 and 38 of Nebuchadnezzar dated from astronomy in 568 and 567 BCE. An astronomical journal (BM 38462)17 list some lunar eclipses in the years 1 to 27 of Nebuchadnezzar which are dated from 604 to 578 BCE.
I think it was pretty brave of Gerard Gertoux to stand up against the WTS tradition publicly and show just why the accepted, evidenced chronology is so difficult to change and try to discredit.

Excellent point made here in the link you provided:
"The durations of the Babylonian reigns, from Eriba-Marduk (770-761) to Nabonidus (556-539), are all known. The chronology of these Babylonian kings is anchored on the dates set by the astronomy of five precisely described lunar eclipses."
Sometimes when we read about Babylonian or Mesopotamian chronology being revised, we think of the Neo-Babylonian period which, unfortunately for the WTS tradition, has been "set in stone" and therefore can't really be revised. 

I would love to discuss the 70-year exile, too, and I'm as tempted to do so as anyone else. So I would also propose a separate thread for discussing the evidence for the years of the exile. But I think we would have a better foundation for any discussion of the BCE years attached to the exile, only after we discuss the basic evidence for the BCE years in the first place. 

There is NO Bible evidence for 539 BCE. There is NO Bible evidence for 587 BCE. There is NO Bible evidence for 607 BCE.
I think most of us understand that by now. So, I propose this new thread/topic where we shift the focus almost exclusively to the basic, fundamental question about the strength of the secular evidence in the Neo-Babylonian period. Why do we rely on it? Why does the WTS rely on secular Babylonian astronomer's evidence for Cyrus in 539? Why does the WTS reject the same evidence for Nebuchadnezzar's 18th year?  Is the evidence for Nebuchadnezzar's years actually 10 times better than for Cyrus?
When that question is solved, it also resolves the entire question about the 70 years, the WTS 20-year gap, the years of those kings that came just before and just after. And it will automatically link to the resolution of dates for events like the Fall of Nineveh, the Battle of Carchemish, the death of Josiah, the years of Zedekiah, the BCE dates for the three different exile events reported in Jeremiah 52. And, of course, it should answer the question about the complete lack of evidence for 607 as Nebuchadnezzar's 18th year.  
So in this new thread/topic there would need to be NO discussion of:
the 70 years of Jewish Exile, or the 70 years of Babylonian domination over other nations the purpose of the WTS 20-year gap 1914 Daniel 4, Gentile Times, the length of the 7 times/years, the length of the 2,520 days making up those 7 years Not even any discussion of Bible prophecies or "70-year" references in: Jeremiah, 2 Chronicles, Isaiah, Zechariah, Daniel.  Just the years of Nebuchadnezzar's reign, and the ACTUAL Neo-Babylonian evidence for it. Any discussion of other topics can be moved back to the topic where this came up and from where I just copied this post. ( https://www.theworldnewsmedia.org/topic/90904-trying-to-nail-down-612-bce-as-the-date-of-ninevehs-destruction/ )

There is NO Bible evidence for 539 BCE. There is NO Bible evidence for 587 BCE. There is NO Bible evidence for 607 BCE. I think most of us understand that by now. So, I propose a thread/topic where we shift the focus almost exclusively to the basic, fundamental question about the strength of the secular evidence in the Neo-Babylonian period. Why do we rely on it? Why does the WTS rely on secular Babylonian astronomer's evidence for Cyrus in 539? Why does the WTS reject the same evidence for Nebuchadnezzar's 18th year?  Is the evidence for Nebuchadnezzar's years actually 10 times better than for Cyrus?
When that question is solved, it also resolves the entire question about the 70 years, the WTS 20-year gap, the years of those kings that came just before and just after. And it will automatically link to the resolution of dates for events like the Fall of Nineveh, the Battle of Carchemish, the death of Josiah, the years of Zedekiah, the BCE dates for the three different exile events reported in Jeremiah 52. And , of course, it should answer the question about the complete lack of evidence for 607 as Nebuchadnezzar's 18th year.  
So in this new thread/topic there would need to be NO discussion of:
the 70 years of Jewish Exile, or the 70 years of Babylonian domination over other nations the purpose of the WTS 20-year gap 1914 Daniel 4, Gentile Times, the length of the 7 times/years, the length of the 2,520 days making up those 7 years Not even any discussion of Bible prophecies or references in: Jeremiah, 2 Chronicles, Isaiah, Zechariah, Daniel.  Just the years of Nebuchadnezzar's reign. Any discussion of other topics can be moved back to this topic/thread.

Turns out that ALL the astronomical events recorded for the entire period agree perfectly well with the Biblical text. Remember that the Biblical text has no BCE dates. There is NO real contradiction between the astronomical events recorded and the Biblical text regarding the Babylonian period.
In fact, the WTS would do much better to follow the same pattern it does for all the other areas where secular history supports the Bible's own version of history. It could be used as evidence to show that there is additional external support for the Bible's accuracy that might have been overlooked.
It's true that there were naysayers about the existence of Belshazzar by Bible skeptics looking for excuses not to trust the Bible. Turns out there wasn't really that much evidence for outright denial, but a lot of skepticism based on other issues with Daniel. But the WTS is guilty of similar skepticism coming from another perspective -- and I don't just mean the admission that no one can identify this Darius the Mede, nor the fact that the WTS rejects the Bible's own chronology of Daniel 1:1 and 2:1. 
Here's an example for another time from "Insight." The Hebrew term transliterated "Ahasuerus" in the Bible is pretty much an expected transliteration for the Persian "Xerxes." (Which can also refer to Artaxerxes.) But notice how the WTS publications deny that the Bible's use of Xerxes/Artaxerxes (Ahasuerus) can refer to him in Ezra, but says it does refer to him in Esther:
*** it-2 p. 613 Persia, Persians ***
From Cyrus’ Death to Darius’ Death. The reign of Cyrus the Great ended in 530 B.C.E. when he died while on a warring campaign. His son Cambyses succeeded him to the throne and was successful in conquering Egypt. Though not referred to by the name Cambyses in the Bible, he is evidently the “Ahasuerus” to whom the opposers of the temple work sent false accusations against the Jews, as stated at Ezra 4:6.
*** it-2 p. 613 Persia, Persians ***
The Reigns of Xerxes and of Artaxerxes. Xerxes, Darius’ son, is evidently the king called Ahasuerus in the book of Esther.
As it turns out, there is really no good reason for the Watchtower to speculate that Ahasuerus/Xerxes is Cambyses in Ezra and Ahasuerus/Xerxes is Xerxes in Esther. The WTS could just as easily have made them both Xerxes and Ezra would actually be giving an even clearer timeline without the unnecessary speculation. I just include it to show how easily and sometimes nonchalantly the WTS will speculate about "outside" history that they believe is contradicted in the Bible. In this case the WTS creates a kind of Bible contradiction about who Ahasuerus was. 
If anyone wishes to discuss, and has the time, there are a few more of these types of WTS-created Bible contradictions, some which might come up anyway in a full discussion of the chronology of the period.

This might be true to a very small extent, but if true, it means that the WTS has no right to claim that 539 BCE was some kind of absolute, pivotal year. 539 is based wholly, 100% on these judgment calls and assumptions. Besides, the date of 587 BCE for the 18th year of Nebuchadnezzar is at least 10 times better documented than the 539 BCE date (for the accession year of Cyrus). 
There are some assumptions used, it's true. But these adjustments or "calibrations" to account for the slowing down of the earth have been known about for a long time. And if we were to use calculations from astronomy today and didn't know about the rate of slowing, we would only be off by about 6 hours going back more than 2700 years. 
That means that the eclipses recorded by Neo-Babylonian/Persian/Greek scholars would still have happened on the same day, but the background stars which were also reported in these records would have passed them up 6 hours earlier. The article you point to is admitting the same thing as this article:
https://www.science.org/content/article/ancient-eclipses-show-earth-s-rotation-slowing
Overall, Earth's spin has slowed by about 6 hours in the past 2740 years, 
 
----- and here comes the tldr; part to ignore ----------
Even without this data we already knew that the earth's day was getting longer just from satellite data from year to year. Even though the day lengthens by only microseconds at a time, it adds up to hundreds of seconds of difference when you go back several centuries. And when you go back 2,700 years (27 centuries) it's a difference that approaches 20,000 seconds (5.5 hours).
That means that when you look for an eclipse, even if you had a good record of the observation for 685 BCE, trying to calculate it without knowing about the earth's slower rotation, would be about 5.75 hours off from the time you expected. That doesn't seem like much time to be off, but it means that the eclipse will likely be seen on the correctly calculated day, but against a background of stars that are nearly half-way across the sky.
The Babylonian "scholars" recorded those stars in the background, so it makes the eclipse seem like it doesn't match any eclipses in the year given.  That is, until you notice that the same pattern holds for ALL the eclipses and that they make a much better fit for the observation when you realize the earth rotated just a wee bit faster back then.
But it's pretty consistent throughout this period:
Near 700 BCE observations hovered around 20,000 seconds off, or 5.5 hours Near 600 BCE observations hovered around 19,000 seconds off or 5.25 hours Near 500 BCE observations hovered around 18,000 seconds off, or 5 hours Near 400 BCE observations hovered around 17,000 seconds off, or 4.75 hours Near 300 BCE observations hovered around 16,000 seconds off, or 4.5 hours Although I'm rounding to the nearest thousand and relying on the article's regression-line analysis to "average" out the anomalies, you can easily see the pattern. And by the time you reach AD/CE readings you would expect closer to 3 hours off, and that's right where the readings end up.
But those lunar eclipse readings can be double-checked by the half-dozen solar readings during the period from 350 to 150 BCE and these line up even closer to the regression line, helping to confirm the same calculations of "delta-T" [change in time].
The point is that this slowdown of the earth's rotation is only a few hours, not days, but when these calibrations are added to the observations and predictions already observed and recorded in ancient Assyria/Babylon/Persia you can now set a specific formula to account for that curve (parabola). That formula is built into all the major astronomy applications which is why they all give the same results. And it turns out that when you do this, the calculations are further confirmed by making an excellent accounting not just of both the lunar and solar data, but also various planetary calculations that the Babylonians also recorded.

Turns out that ALL the astronomical events recorded for the entire period agree perfectly well with the Biblical text. Remember that the Biblical text has no BCE dates. There is NO real contradiction between the astronomical events recorded and the Biblical text regarding the Babylonian period.
In fact, the WTS would do much better to follow the same pattern it does for all the other areas where secular history supports the Bible's own version of history. It could be used as evidence to show that there is additional external support for the Bible's accuracy that might have been overlooked.
It's true that there were naysayers about the existence of Belshazzar by Bible skeptics looking for excuses not to trust the Bible. Turns out there wasn't really that much evidence for outright denial, but a lot of skepticism based on other issues with Daniel. But the WTS is guilty of similar skepticism coming from another perspective -- and I don't just mean the admission that no one can identify this Darius the Mede, nor the fact that the WTS rejects the Bible's own chronology of Daniel 1:1 and 2:1. 
Here's an example for another time from "Insight." The Hebrew term transliterated "Ahasuerus" in the Bible is pretty much an expected transliteration for the Persian "Xerxes." (Which can also refer to Artaxerxes.) But notice how the WTS publications deny that the Bible's use of Xerxes/Artaxerxes (Ahasuerus) can refer to him in Ezra, but says it does refer to him in Esther:
*** it-2 p. 613 Persia, Persians ***
From Cyrus’ Death to Darius’ Death. The reign of Cyrus the Great ended in 530 B.C.E. when he died while on a warring campaign. His son Cambyses succeeded him to the throne and was successful in conquering Egypt. Though not referred to by the name Cambyses in the Bible, he is evidently the “Ahasuerus” to whom the opposers of the temple work sent false accusations against the Jews, as stated at Ezra 4:6.
*** it-2 p. 613 Persia, Persians ***
The Reigns of Xerxes and of Artaxerxes. Xerxes, Darius’ son, is evidently the king called Ahasuerus in the book of Esther.
As it turns out, there is really no good reason for the Watchtower to speculate that Ahasuerus/Xerxes is Cambyses in Ezra and Ahasuerus/Xerxes is Xerxes in Esther. The WTS could just as easily have made them both Xerxes and Ezra would actually be giving an even clearer timeline without the unnecessary speculation. I just include it to show how easily and sometimes nonchalantly the WTS will speculate about "outside" history that they believe is contradicted in the Bible. In this case the WTS creates a kind of Bible contradiction about who Ahasuerus was. 
If anyone wishes to discuss, and has the time, there are a few more of these types of WTS-created Bible contradictions, some which might come up anyway in a full discussion of the chronology of the period.

This might be true to a very small extent, but if true, it means that the WTS has no right to claim that 539 BCE was some kind of absolute, pivotal year. 539 is based wholly, 100% on these judgment calls and assumptions. Besides, the date of 587 BCE for the 18th year of Nebuchadnezzar is at least 10 times better documented than the 539 BCE date (for the accession year of Cyrus). 
There are some assumptions used, it's true. But these adjustments or "calibrations" to account for the slowing down of the earth have been known about for a long time. And if we were to use calculations from astronomy today and didn't know about the rate of slowing, we would only be off by about 6 hours going back more than 2700 years. 
That means that the eclipses recorded by Neo-Babylonian/Persian/Greek scholars would still have happened on the same day, but the background stars which were also reported in these records would have passed them up 6 hours earlier. The article you point to is admitting the same thing as this article:
https://www.science.org/content/article/ancient-eclipses-show-earth-s-rotation-slowing
Overall, Earth's spin has slowed by about 6 hours in the past 2740 years, 
 
----- and here comes the tldr; part to ignore ----------
Even without this data we already knew that the earth's day was getting longer just from satellite data from year to year. Even though the day lengthens by only microseconds at a time, it adds up to hundreds of seconds of difference when you go back several centuries. And when you go back 2,700 years (27 centuries) it's a difference that approaches 20,000 seconds (5.5 hours).
That means that when you look for an eclipse, even if you had a good record of the observation for 685 BCE, trying to calculate it without knowing about the earth's slower rotation, would be about 5.75 hours off from the time you expected. That doesn't seem like much time to be off, but it means that the eclipse will likely be seen on the correctly calculated day, but against a background of stars that are nearly half-way across the sky.
The Babylonian "scholars" recorded those stars in the background, so it makes the eclipse seem like it doesn't match any eclipses in the year given.  That is, until you notice that the same pattern holds for ALL the eclipses and that they make a much better fit for the observation when you realize the earth rotated just a wee bit faster back then.
But it's pretty consistent throughout this period:
Near 700 BCE observations hovered around 20,000 seconds off, or 5.5 hours Near 600 BCE observations hovered around 19,000 seconds off or 5.25 hours Near 500 BCE observations hovered around 18,000 seconds off, or 5 hours Near 400 BCE observations hovered around 17,000 seconds off, or 4.75 hours Near 300 BCE observations hovered around 16,000 seconds off, or 4.5 hours Although I'm rounding to the nearest thousand and relying on the article's regression-line analysis to "average" out the anomalies, you can easily see the pattern. And by the time you reach AD/CE readings you would expect closer to 3 hours off, and that's right where the readings end up.
But those lunar eclipse readings can be double-checked by the half-dozen solar readings during the period from 350 to 150 BCE and these line up even closer to the regression line, helping to confirm the same calculations of "delta-T" [change in time].
The point is that this slowdown of the earth's rotation is only a few hours, not days, but when these calibrations are added to the observations and predictions already observed and recorded in ancient Assyria/Babylon/Persia you can now set a specific formula to account for that curve (parabola). That formula is built into all the major astronomy applications which is why they all give the same results. And it turns out that when you do this, the calculations are further confirmed by making an excellent accounting not just of both the lunar and solar data, but also various planetary calculations that the Babylonians also recorded.

True. The last person at the Watch Tower Headquarters who was called Pastor, evidently never owned a car. The newspaper article starts out: Pastor Russell of the Peoples Pulpit Association today declared that he would use the yacht, Angel, presented to him by his association . . .

This might be true to a very small extent, but if true, it means that the WTS has no right to claim that 539 BCE was some kind of absolute, pivotal year. 539 is based wholly, 100% on these judgment calls and assumptions. Besides, the date of 587 BCE for the 18th year of Nebuchadnezzar is at least 10 times better documented than the 539 BCE date (for the accession year of Cyrus). 
There are some assumptions used, it's true. But these adjustments or "calibrations" to account for the slowing down of the earth have been known about for a long time. And if we were to use calculations from astronomy today and didn't know about the rate of slowing, we would only be off by about 6 hours going back more than 2700 years. 
That means that the eclipses recorded by Neo-Babylonian/Persian/Greek scholars would still have happened on the same day, but the background stars which were also reported in these records would have passed them up 6 hours earlier. The article you point to is admitting the same thing as this article:
https://www.science.org/content/article/ancient-eclipses-show-earth-s-rotation-slowing
Overall, Earth's spin has slowed by about 6 hours in the past 2740 years, 
 
----- and here comes the tldr; part to ignore ----------
Even without this data we already knew that the earth's day was getting longer just from satellite data from year to year. Even though the day lengthens by only microseconds at a time, it adds up to hundreds of seconds of difference when you go back several centuries. And when you go back 2,700 years (27 centuries) it's a difference that approaches 20,000 seconds (5.5 hours).
That means that when you look for an eclipse, even if you had a good record of the observation for 685 BCE, trying to calculate it without knowing about the earth's slower rotation, would be about 5.75 hours off from the time you expected. That doesn't seem like much time to be off, but it means that the eclipse will likely be seen on the correctly calculated day, but against a background of stars that are nearly half-way across the sky.
The Babylonian "scholars" recorded those stars in the background, so it makes the eclipse seem like it doesn't match any eclipses in the year given.  That is, until you notice that the same pattern holds for ALL the eclipses and that they make a much better fit for the observation when you realize the earth rotated just a wee bit faster back then.
But it's pretty consistent throughout this period:
Near 700 BCE observations hovered around 20,000 seconds off, or 5.5 hours Near 600 BCE observations hovered around 19,000 seconds off or 5.25 hours Near 500 BCE observations hovered around 18,000 seconds off, or 5 hours Near 400 BCE observations hovered around 17,000 seconds off, or 4.75 hours Near 300 BCE observations hovered around 16,000 seconds off, or 4.5 hours Although I'm rounding to the nearest thousand and relying on the article's regression-line analysis to "average" out the anomalies, you can easily see the pattern. And by the time you reach AD/CE readings you would expect closer to 3 hours off, and that's right where the readings end up.
But those lunar eclipse readings can be double-checked by the half-dozen solar readings during the period from 350 to 150 BCE and these line up even closer to the regression line, helping to confirm the same calculations of "delta-T" [change in time].
The point is that this slowdown of the earth's rotation is only a few hours, not days, but when these calibrations are added to the observations and predictions already observed and recorded in ancient Assyria/Babylon/Persia you can now set a specific formula to account for that curve (parabola). That formula is built into all the major astronomy applications which is why they all give the same results. And it turns out that when you do this, the calculations are further confirmed by making an excellent accounting not just of both the lunar and solar data, but also various planetary calculations that the Babylonians also recorded.

I really like the fact that you are trying to work it out for yourself.
Because I was always so skeptical of the accepted, secular chronology I thought it was important to "start from scratch" and work the whole thing out for myself. 
I think most Witnesses don't realize that ANY time we see a B.C.E. date in the WTS publications, it means that we are relying on SECULAR chronology.
Personally, I'm convinced that the Bible is sufficient on its own to keep us fully equipped, therefore without any need to rely on secular chronology, so I give no special credence or reliance to any specific years with a BCE date attached to them. Doesn't mean they can't be helpful in trying to figure out the order of events, but even here, those secular dates aren't necessary in order to understand the Bible, and figure out the order of Biblical events. 
And from a purely Biblical perspective we aren't going to get any definite mentions of an eclipse or some other astronomical event that is tied to a specific month and day and year of a specific king. Therefore there can be no BCE dates calculated from the Bible. 
In my opinion, there are two main stumbling blocks that always hamper any chronology discussion, and they are related:
Witnesses are told that we are defending Biblical chronology based on a pivotal ('absolute') date of 539 BCE and the Biblical 70 years.  When arguing with Witnesses, Non-Witnesses don't (or won't) admit that the most logical and common-sense understanding of the 70 years favors the WTS viewpoint. 

Trolls-R-Us: @BTK59 @BillyTheKid-55 @George88 @Allen Smith @AllenSmith35 @Alphonse and many more.
What would this forum be like without them?

https://biblearchaeology.org/about/abr-research-projects/the-daniel-9-24-27-project?amp;view=category&id=69&start=16

I'm using this thread to organize some things.

https://en.wikipedia.org/wiki/List_of_kings_of_Babylon
https://www.rcyoung.org/articles/Eclipse1.pdf
https://www.britannica.com/science/eclipse/Assyrian

I only meant that for those of us who have watched this phenomenon for years, we can easily spot it. 
Then again, when someone needs you to explain something a dozen times over the course of several months, and several threads (like your use of the term "carrion") but they still come back with the exact same retort . . . well sometimes you can just 'smell' it:

I only meant that for those of us who have watched this phenomenon for years, we can easily spot it. 
Then again, when someone needs you to explain something a dozen times over the course of several months, and several threads (like your use of the term "carrion") but they still come back with the exact same retort . . . well sometimes you can just 'smell' it:

I only meant that for those of us who have watched this phenomenon for years, we can easily spot it. 
Then again, when someone needs you to explain something a dozen times over the course of several months, and several threads (like your use of the term "carrion") but they still come back with the exact same retort . . . well sometimes you can just 'smell' it:

Thanks for making me feel my own idiocy with even more intensity!
I've been idling in the background for too long, and apparently it's showing. But I like idle!

LOL. I've avoided outing him directly for a couple of years, although I drop a hint now and then for newcomers to the forum like yourself.
It's part of this forum's history now over the last 10 years to have had at least 40+ names show up that were really all the same person. He has rarely been able to juggle more than 3 or 4 to be active at the same time. You have already blocked his G88 persona, but he always keeps a couple of other accounts active as backups, as sock puppets, and as proxies to upvote himself and downvote others. Fortunately, he tries pretty hard to remain serious for a while, but typically devolves into a lot of dissention and insults before too long. For those of us who have participated for several years, it's unbelievably easy to spot his doppelgangers by repeated vocabulary, repeated attacks, repeated ideas, and repeated non-ideas. He is apparently not aware how easily he gives himself away through some other factors I'll keep to myself for now, even though several others here have already mentioned those factors elsewhere. If no one takes themselves too seriously, it can be terribly entertaining, in a unique sort of way.