dragon's head and tail
this is a question that i've posted among other comments time ago. i'm still seeking for the anwser. could anybody tell me when the ancient talked about the 'dragon's head (tail)', were they using the true or mean measure? for example, in Tetrabiblos, the dragon head is "mean" or "true"? could Ptolemy already calculated the mean Nodes movement? thanks is anybody could comment on this question.