The chronological tables work in conjunction with other qualifying information. Everything is clearly outlined here;
http://onlytruegod.org/jwstrs/537vs539.htm
Some critics have suggested that Jehovah's Witnesses have concocted an unorthodox and dishonest explanation in asserting that the seventy years of desolation ended in 537 B.C.E. Is this claim substantiated?
No. At Ezra 1:1, reference is made to "the first year of Cyrus," not "the year Cyrus became king" (or accession year), so he was speaking of the first regnal year of Cyrus, which cuneiform documentation places in 538/537 B.C.E. Jewish historian Josephus corroborates by referring to "the first year of the reign of Cyrus."—Antiquities of the Jews, Book XI, Chapter I.
This point is generally agreed upon by historians. For instance, the Handbook of Bible Chronology by Jack Finegan (Princeton University Press, 1964), p. 170, states: Handbook of Bible Chronology by Jack Finegan (Princeton University Press, 1964), p. 170, states:
"The biblical references to the first year of Cyrus when he made the proclamation which allowed the Jewish exiles to return from Babylon to Jerusalem (II Ch 36:22f.; Ezr 1:1f.) are presumably stated in terms of his reign in Babylon since they deal with an event in that city. According to the cuneiform evidence and the Babylonian calendar, Babylon fell on Tashritu 16 = Oct 12, 539 B.C., and Cyrus entered the city two and one-half weeks later on Arahsamnu 3 = Oct 29. His Babylonian regnal years began, therefore, as shown in Table 77. Accordingly his first year, in which he made the proclamation, was 538/537 B.C."
TABLE 77. BABYLONIAN REGNAL YEARS OF CYRUS
AT THE BEGINNING OF HIS REIGN
Accession 539/538
Year 1 538/537
Year 2 537/536
The Watchtower of May 1, 1952, pp. 271-2 further observes:
"In late years several cuneiform tablets have been discovered pertaining to the fall of Babylon which peg both Biblical and secular historic dates. The one tablet known as the "Nabunaid Chronicle" gives the date for the fall of Babylon which specialists have ascertained as being October 12-13, 539 B.C., Julian Calendar, or October 6-7, 539 B.C., according to our present Gregorian Calendar. This tablet also says that Cyrus made his triumphant entry into Babylon 16 days after its fall to his army. Thus his accession year commenced in October, 539 B.C. However, in another cuneiform tablet called "Strassmaier, Cyrus No. 11" Cyrus’ first regnal year is mentioned and was determined to have begun March 17-18, 538 B.C., and to have concluded March 4-5, 537 B.C. It was in this first regnal year of Cyrus that he issued his decree to permit the Jews to return to Jerusalem to rebuild the temple. (Ezra 1:1) The decree may have been made in late 538 B.C. or before March 4-5, 537 B.C.
In either case this would have given sufficient time for the large party of 49,897 Jews to organize their expedition and to make their long four-month journey from Babylon to Jerusalem to get there by September 29-30, 537 B.C., the first of the seventh Jewish month, to build their altar to Jehovah as recorded at Ezra 3:1-3. Inasmuch as September 29-30, 537 B.C., officially ends the seventy years of desolation as recorded at 2 Chronicles 36:20, 21, so the beginning of the desolation of the land must have officially begun to be counted after September 21-22, 607 B.C., the first of the seventh Jewish month in 607 B.C., which is the beginning point for the counting of the 2,520 years."
