. Astrologers are sometimes known as astrologists. Historically the term mathematicus was used to denote a person proficient in astrology, astronomy, and mathematics. Practice In the United States, the practice of astrology is largely unregulated. Certification isn't required by legislation for an astrologer to offer his or her services. However, there are various examinations offered by private organizations such as the American Federation of Astrologers and the National Council for Geocosmic… (More on Astrologer)