The Diary begins in Year 37 of Nebukadnezar, Month 1, the 1st day which authors Sachs & Hunger identify as -567, Apr 22/23. The tablet has 19 lines on one side (Obv), 21 on the other (Rev), and a few more along the edges. Much of the text is lost. Only a section of the tablet survives and some of the inscriptions have deteriorated. Still, the tablet logs more than 40 readable astronomical observations.
Of more than 40 observations tallied in the Diary, all but 3 entries closely match computed values.
Additionally, several correlations are not clear-cut. For example, Line 2 logs Saturn was in front of the Swallow. TheSky software computes Saturn in Pisces, which is the constellation associated with the Swallow. However, the Swallow is ill-defined. It may denote a part of the whole constellation, or a particular star within Pisces. Thus the match is satisfactory, but imprecise.
There was 1 obvious scribal error in Diary No. -567. Computer skyshots demonstrate that Line 3: Night of the 9th should read Night of the 8th.
Diary Line 14 logs, Night of the 5th, beginning of the night, the moon passed towards the east 1 cubit [above/below] the bright star at the end of the Lion's foot.
At sunset on June 24th (night of the 5th), TheSky computes the moon was high in the western sky, nowhere near a "bright star at the end of the Lionís foot." The Skyshot shows the moon in Virgo. It had passed through Leo a couple of days earlier, at which time it was nearby Venus. (See SkyShot) Clearly, the computed position of the moon does not match the Diary record.
A noteworthy divergence crops up in the analysis of Line 16 The 12th, one god was seen with the other, sunrise to moonset: 1° 30'.
Translated in modern terms: On the morning of the 12th (Mar 26, -566), a sliver of the moon was visible in the western sky as the sun rose in the east. Then the moon set 6 minutes later (1° 30').
However, TheSky software shows the moon was no longer in the sky at sunrise on the morning of Mar 26th. It had set 3 minutes prior to sunrise rather than 6 minutes afterwards - a difference of 9 minutes.
The 9-minute difference between Diary Line 16' and TheSky software may have come about in several ways. Line 16' mentions a little rain, which suggests viewing conditions were not optimum. Possibly, modern astronomical computation is at fault. Still, how significant is 9 minutes over a span of more than 2500 years?
In the course of 2500 years, a clock tick tocks in excess of 1,300,000,000 minutes. Thus the mismatch in Line 16' of 9 minutes corresponds to an "error" of less than 1 in 10E8 (one part in 100 million) in the orbital position of the moon.
The result indicates Babylonian astronomers were fine observers, and modern astronomical computations are excellent.
The first 10 datable inscriptions of Diary No. -197 were analyzed in the same manner as the data of Diary No. -567.
After testing these observations and finding few significant discrepancies, the analysis of Diary No. -197 was curtailed.
(To be precise, of the more than 15 independent phenomena considered, 2 mismatches warranted further investigation.)
Another 8 Diary inscriptions were analyzed using TheSky software. The inscriptions were selected randomly, but with the added purpose of illustrating the characteristic phenomena that Babylonian astronomers watched for in mapping the sky.
The study found no significant discrepancies. The overall integrity of Babylonian astronomy and modern computation seems firm.