Reference:
Mathieu Ossendrijver (Berlin) Translating Babylonian Astronomical Diaries and Procedure Texts
“Behind”: the Akkadian word, arki, is abbreviated to ar2. The directions “behind” and “in front of” are defined in relation to the daily rotation of the sky which proceeds from east to west for an observer in the northern hemisphere, i.e. “behind” is “to the east of”, and “in front of” is “to the west of”.