Mechanism to adjudicate Astrological Divination

In the campaign Khareo's Tale, a lot of the plot revolves around astrological divination rituals. Knowing what to provide as the outcome of a divination spell can be difficult to gauge. This is particularly so if you want to consistently scale the usefulness of the information with respect to the margin of success. This post describes how we are doing it on our campaign. 


This is a joint post with Sophie Blouin, who brainstormed with me and had the idea of buying destinies using powerful prophecies (which I find very cool). 

In a nutshell

Astrological divination is concerned with position and timing. The better is the divination roll, the more precise is the prediction in these two scopes. Astrology is a ritual subject to normal ritual modifiers (GURPS Thaumatology) and some specific one about the object of the divination. A star chart prop was designed to simplify the adjudication of divination checks. 

The star chart. The number indicate the MoS cost of each area.
Latin is used for flavor, but the English word is shown in smaller print.

This post is further divided into three sections: Ritual Magic modifiers, Interpreting the results and examples.