On the 3rd Sept 1929 Saturn was 23 Sag 55, the high just before the 1929 Great Crash which lead to the Great Depression. This degree then becomes a pivot especially for monthly analysis. In his ephemeris, Gann noted that on the 1st May 1944, Saturn would be 180 or opposite itself, at 23 Gem 55. This is a half cycle or 2nd Harmonic of the Saturn cycle of 29.5 years.
Sagittarius and Gemini are mutable signs and have a specific pattern for the Dow Jones, which I explain more in my newest presentation The Prophetic 7 year Shemitah Cycle and the Blood Moons. You will learn the Astrological cycles behind the biblical Shemitah 7 year cycle.