> “[The tablet] is a copy of the night notebook of a Sumerian astronomer as he records the events in the sky before dawn on the 29 June 3123 BC”

I'm pretty sure clay tables, that had to be fired to preserve them, did not function as "notebooks". Scribes probably used either unbaked clay or wax tablets to take notes, and they would erase and overwrite them constantly like etch-a-sketch.