Measuring the Wavelength of the Dominant Cycle

An important first step in making sense of MESA’s indications is to read MESA’s measurement of the wavelength of the dominant cycle.

The simple definition of the dominant cycle is the cyclic component identified by MESA that has the greatest amplitude. The dominant cycle is described by its wavelength, measured in bars. In order to prevent dramatic but short-lived variations in the dominant cycle, instead of just taking the measured wavelength of the cyclic component with the greatest amplitude, Aspen Systems’ MESA studies filter the dominant cycle a little further. First, the dominant cycle wavelength is only permitted to change by 25% from bar to bar. Second, the result of the 25% limit criterion is then fed into a 3-bar exponential moving average, using the previous two bars’ dominant-cycle calculations as the other inputs. The resulting wavelength identifies the current bar’s dominant cycle.

You can read the wavelength of the dominant cycle in two places on the recommended MESA screen setup. One is from the MESA Standard Prediction: if you position the prediction on the current bar, the prediction study shows one cycle’s worth of history of the dominant cycle. So you can count the number of bars (not including the current bar) in that historic cycle, moving the red cursor back with the left cursor key to keep your place.

The other place to read the dominant cycle is from the MESA Spectrum study. The green line in the colorful spectrum contour plot in the main study window shows the wavelength of the dominant cycle. Just position the point of the mouse arrow on the green line at the current bar, and read the value off the wavelength scale on the vertical axis. Odd wavelengths fall between the gradations, but you can read the wavelength exactly.