The solar cycle has a profound effect on both terrestrial and extra-terrestrial operations. Understanding the history of the solar cycle is necessary for studying long term trends, however older data is difficult to calibrate due to the sparsity of observations. In this paper we propose a new method for calibrating sunspot number data that does not rely on observational overlap. Initial testing shows promise in this method’s success, though more work must be done to ensure calibration consistency across all observers.
Hollenbach, Sam Q.
"Understanding Solar Activity During the Last 400 Years,"
Macalester Journal of Physics and Astronomy: Vol. 7:
1, Article 4.
Available at: https://digitalcommons.macalester.edu/mjpa/vol7/iss1/4