A branch of astrology seeking to explain an event from its timing. Robert Schmidt says: "For example, suppose you receive a letter or message from someone and you wish to know the intentions of the sender, whether the message was tampered with in some way, etc.; to find these things out, cast the chart for the moment you received the letter. Or suppose you wish to know the course of someone's illness; cast the chart for the moment he took to his bed." See Decumbiture.