Donald Bradley Siderograph Formula 11

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.

Table of Bradley Siderograph Major Aspects


See the table below for a depiction of how the Bradley Siderograph Model generally provides greater weights to planets that have longer synodic periods.

Bradley Siderograph Formula - Table of Medium Terms and Long Terms

Bradley Siderograph 2014

See the results of the bradley siderograph formula for this year — check out the Bradley Siderograph 2014 turn dates.

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11 thoughts on “Donald Bradley Siderograph Formula

  • Vikalp

    What is the meaning of power in siderograph. Only the dates with a power value of 100/100 shall be considered ? How it is calculated ?

    • Bradley Siderograph

      Hi Vikalp,

      Thanks for your comment. At a high level, the “Power” is calculated by determining the extent to which the value of an indicator on a particular day is either (1) a relatively high value or (2) a relatively low value. My rationale for creating the “Power” concept was to quantify the Turn Dates more precisely rather than relying largely on judgment to determine which dates are true “Turn Dates.”

      Here is an overview of the calculations that go into determining the “Power” for a certain date.

      First, determine if the value of the indicator for a certain date is the highest value looking back and forward 1 day, 2 days, 3 days, so on and so forth. The maximum value that is registered is 365 days, which would be reached if the value of the indicator for a certain day is the highest or lowest value looking back one year and forward one year. I judgmentally capped the maximum value at 365 because I thought a two year period (i.e., one year looking backward and one year looking forward) was about right for this metric.

      Then, once you have the value from the step above, you divide it by 365. Finally, multiply it by 100 to “scale it up” and then round it to the nearest whole number.

      Here’s an example, which should help make this easier to understand. On September 3, 2017 there is a Long Terms Turn Date with a Power of 49/100. On this date the Long Terms value is the lowest looking back and forth 215 days. If we divide 215 days by 365 days we arrive at a value of 0.589. We then scale it up by multiplying it by 100 and then rounding it to the nearest whole number, which allows us to arrive at the “Power” of 59/100 for the Long Terms Turn Date on September 3, 2017 (i.e., 215 days/365 * 100 = power of approximately 59).

      The actual calculations are a little more nuanced than that, but this should give you a good sense for how it is calculated.


  • jayesh

    Do u have a software/excel sheet for forex pairs? also whether it can be used for short term trades, swing trades or positional trades or for all of them. pl. also mention the pricing.

    • Bradley Siderograph

      Hi Jayesh,

      Aside from the Bradley Siderograph, the main software/Excel that is currently available for forex pairs would be the Advanced Astro Dashboards. Here you can find a listing of the forex Dashboards that are currently available:

      The Bradley Siderograph has historically been viewed as a way to identify possible turning points in investor sentiment. This can lead to what are known as “inversions” (i.e., where the Bradley Siderograph makes a high and the price of a security hits a low). Therefore, with respect to the Bradley Siderograph there is usually a greater focus on possible “turns” (i.e., up or down) in investor sentiment on Turn Dates.

      In contrast, the weights used to derive the Advanced Astro Indicator are unique to each individual security or forex pair. For example, if a particular security has tended to go up upon the occurrence of a particular planetary aspect historically, the weight for that aspect would be positive. This is the opposite of the Bradley Siderograph, which assumes all trine aspects (120 degrees) are positive and that all square aspects (90 degrees) are negative with respect to investor sentiment. Given that this process uses weights based on historical correlations that are customized to each security, there is a separate Advanced Astro Dashboard for each security.

      Each Advanced Astro Dashboard is currently available for $39. The Dashboards will allow you to see how the forex pair you are analyzing has performed relative to each indicator (e.g., Bradley Siderograph, Long Terms, Advanced Astro Indicators, etc.). There is also a new tab that will display updated historical correlations between the security and each indicator (i.e., the correlations will update each time you import updated historical price data into the Dashboard). There is also a tab that shows when each planetary aspect is taking place (e.g., so you can notice if there are patterns between certain planetary aspects taking place and large wings in the price of a particular security). Next to each of these planetary aspects there is an indication of the actual historical correlation between that planetary aspect and a particular security.

      $39 for each Dashboard is a great value for all that it includes. However, if you’re looking for an even better value you can obtain the Dashboards for all of the currently available forex pairs for $125 or all the dashboards for all securities for $197. See below for additional details:


  • krishna attri

    dear sir

    I am doing work in Indian stock market & want use your excel software for indian stock market.can u tall me how can I use ur software & how can I buy this.

    • Bradley Siderograph

      Hi Krishna,

      On the Advanced Astro Indicator page ( you will find two green button that say “NIFTY 50 (India)” and “SENSEX (India),” which you can use to obtain the software for the Indian Stock Market.

      Also, within the next couple of days I’m planning to add several additional India-related securities to the Advanced Astro Indicator page including Lupin (India NSE), LIC Housing Fin Ltd (India NSE), Tata Steel Ltd (India NSE), USD/INR (U.S. Dollar and Indian Rupee).

      The Full Version of the Advanced Astro Dashboard comes with access to all of these securities as well as all other securities for which there is an Advanced Astro Dashboard. After I update the site in the next couple of days you will see that there are now 93 securities total that have an Advanced Astro Dashboard.


  • ramesh patel

    i want your softwer for indina stock markets and commoditeis markets so please replay me for haw many price your software ya data prices pack