See the video below for a brief overview of the formula underlying the Bradley Siderograph.
The equation for the Bradley Siderograph indicator is calculated as follows:
[ (5) X (Long Term Sums Value + Declination Value Sums) ] + (Middle Term Value Sums)
The factor of five in the formula provides a greater weight to (1) the planetary aspects considered to be “Long Terms” and (2) declinations. The Middle Terms represent planetary aspects that are important but that receive less weight than the Long Terms.
However, note that in his book, “Stock Market Prediction,” Donald Bradley offered some flexibility in the choice of the appropriate weight to use for the Long Terms. He wrote that the Long Terms “may be given considerably more weight by multiplying it 3, 4, or 5 times, depending upon choice after experimentation.” For this site I used a multiplier of 5 for the Long Terms.
Long Terms, Middle Terms, and Short Terms
There are a total of 36 planetary aspects taken into account in the siderograph and of these:
- Long Term Aspects — 10 of of the 36 aspects are considered Long Term. These are generally aspects between the farther-out slower moving planets (e.g., Jupiter, Saturn, etc.), so Bradley thought they should receive a greater weight.
- Middle Term Aspects — 26 of the 36 aspects are considered Middle Term. These aspects include the Sun and the faster moving planets from Mercury through Mars.
- Short Term Aspects — 0 of the 36 aspects are considered Short Term. Bradley classified aspects with the moon as Short Term, which he believed believed had an effect for only a period of hours. Therefore, Short Term aspects are not incorporated in the Bradley Siderograph because they are not anticipated to have an effect the overall market behavior over the medium to long term).
Table of Aspects, Synodic Periods, and Long/Middle Term Classifications
See the table below for the planetary aspects that are incorporated into the Bradley siderograph. Note that the slower moving planets with greater synodic periods (e.g., Jupiter and the farther out planets) compose the Long Term aspects and receive a weight that is five times that of the Medium Terms. A synodic period between two planets is the amount of time that elapses between planetary conjunctions of the two planets. In his book “Planetary Stock Trading IV,” Bill Meridian, a leading author in the field of Financial Astrology, noted that “a basic tenet of astrology is that the slower a planet moves, the greater its strength. Outer planets are the slowest.” Therefore, it makes sense that the slower moving farther out planets receive a higher weight in the Bradley Siderograph.
See the Major Planetary Aspects page for a description of planetary conjunctions.
See the table below for a depiction of how the Bradley Siderograph Model generally provides greater weights to planets that have longer synodic periods.