2. Regular Watching

The archaic cuneiform script of the Diaries records astronomical and related observations.  The earliest of these "regular watchings," as the Babylonians called them, is dated to 652 BCE (-651), the latest to 61 BCE (-60).

Historians have worked out dates for 180 of the surviving Diaries.  These are published in a three volume set, Astronomical Diaries and Related Texts from Babylonia by Sachs & Hunger (1988-98).  The books include photographs of the tablets, transliteration of the cuneiform text, and an English translation.