Astrologers are influenced by many astrological lineages. The oldest include Babylonian, Hellenistic, Arabic, Medieval, and the Classical astrology of the 15th & 16th Centuries. The practice of many modern astrologers can trace their roots to the Theosophical and Esoteric movement of Helena Blavatsky, Alice Baily, Bessie Besant, Rudolf Steiner and Max Heindal. This perspective mixed with the psychological perspective in the writings of Marc Emund Jones and Dane Rudhyar. In the New Age Movement of the 1960s and 1970s, you have the added influence of the humanistic perspective from astrologers such as Michael Meyer. In addition, there is a profileration of planetary bodies with the addition of the asteroids and new looks at astrology such as Uranian. In the late 1970's, many astrologers begin to emphasize the outer planets and the moon's nodes leading to the recent spiritual perspective of Evolutionary Astrologers.
Rectification of a birth horoscope is the process of using the birth chart and astrological timing methods to test and clarify the true birth time of an individual. Since it might well be considered the Mount Everest or Holy Grail of astrological exercises: very challenging, fraught with errors, a low likelihood of success, and a high chance of failure - why then, attempt it? When no birth time is available or if there are multiple conflicting reports, the rectification exercise resembles the challenge of searching half the Indian Ocean for a missing jetliner. But a successful rectification opens up the possibility of a high degree of accuracy in prediction, particularly if it is based upon a timed-tested tradition.