A midpoint is a mathematical point halfway between two stellar bodies that tells an interpretative picture for the individual.
Guido Bonati used direct midpoints (1123–1300) in the 13th century to refine timings in an event chart.
Alfred Witte was the first person to do a lot of investigation on midpoints using movable dials and together with Ludwig Rudolph and Herman Lefeldt formed the Hamburg School of Astrology and the technique with the use of Trans Neptunian points was called the Uranian Astrology.
[2] Then, Reinhold Ebertin in his book Combination of Stellar influences[3] included psychological principles and simplified the midpoint technique, removing the Trans Neptunians used by the Hamburg School.
These were further popularized by American authors Aren Ober (formerly Savalan) and Eleanor Kimmel.