Scholar,
So what1 I am fully aware about the secular evidence for the Nabonidus Chronicle for it used to determine the calender year for the fall of Babylon in 539.
Like I said, dating the year of the fall of Babylon to 539BC has nothing to do with the Nabonidus Chronicle. The year (17) of Nabonidus in the text is missing, and has to be restored using three other sources, Ptolemy's Canon, the Greek Olympiad year reckoning and what else? That's right, an astronomical text, 'Strm Kambys 400'.
The easiest way to work out the fall of Babylon is to use ancient historians who place Cyrus' last year as Olympiad 62;2 (531/530 BC) and then use cuneiform tablets that give a 9 year rule for Cyrus at Babylon to give a start date of 539BC. Unfortunately, the society then rejects other dates by these historians for the 20th year of Artaxerxes, which you must admit is very inconsistent. Then again, judging by your comments, you seem to think it is o.k. to pick and choose evidence that fit prophetic speculation, and reject evidence that contradicts.
So since the Watchtower society inconsistently rejects certain quotes from ancient historians, whilst agreeing with other quotes, we are left with astronomical text Strm Kambys 400. It is difficult to know whether the eclipses on this tablet are actually observations or predictions. In fact it is far better to use an astronomical text such as BM 38462 and the many others that exist, and then count forward to 539 BC. So starting from 16th March 597 BC as the first capture of Jerusalem at the end of Nebuchadnezzar's seventh year and using the known lengths of the neo-Babylonian kings (66 years in total) to count forward we get to 539/538 BC.
Now using the Nabonidus Chronicle, which still have the month and day of Babylon's fall preserved as 16th Tishri, the date can be calculated to 13th October 539 BC.
CF.