Astrology

This proficiency gives the character some understanding of the supposed influences of the stars. Knowing the birth date and time of any person, the astrologer can study the stars and celestial events and then prepare a forecast of the future for that person. The astrologer's insight into the future is limited to the next 30 days. and his knowledge is vague at best. If a successful proficiency check is made, the astrologer can foresee some general event — a great battle, a friend lost, a new friendship made, etc. The DM decides the exact prediction (based on his intentions for the next few gaming sessions). Note that the prediction does not guarantee the result—it only indicates the potential result. If the proficiency check is failed, no information is gained unless a 20 is rolled. in which the prediction is wildly inaccurate.

Clearly this proficiency requires preparation and advance knowledge on the part of the DM. Because of this, it is permissible for the DM to avoid the question, although this shouldn't be done all the time. Players who want to make their life easier (always a good idea) should consider using this proficiency at the end of a gaming session, giving the DM until the next session to come up with an answer. The DM can use this proficiency as a catalyst and guide for his adventures—something that will prompt the player characters to go to certain places or to try new things.

Characters with the astrology proficiency gain a +1 bonus to all Navigation proficiency checks, provided the stars can be seen.

Dwarven Astrology Proficiency

Astrology is only available to dwarves who live on or near the surface of the world. Deep dwarves and others who do not have easy access to the surface do not have the astrology proficiency. In order to use astrology, you have to see the stars.

[Player's Handbook]
[Complete Book of Dwarves]