As amateur radio operators, we are familiar with the 10 to 11 year sunspot cycle.
This cycle was discovered 175 years ago by German astronomer Samuel Heinrich Schwabe in 1843.
Swiss astronomer/mathematician Rudolf Wolf came up with a way to compute sunspot numbers in 1848 and we’ve been observing it ever since.
Based on data collected from different researchers and different locations and by assigning a scaling factor, we have a good idea beginning about 1750. Anything earlier is subjective data, at best.
German astronomer Gustav Sporer was first to note a prolonged period of low sunspot activity from 1645 to 1715. The *possible* absence of sunspots for this period was supported by compiling data from Rudolf Wolf.
English meteorologist John Dalton was first to notice these sunspot minimums coincided with lower-than-average global temperatures.
Sporer’s work was summarized by Irish astronomers/mathematicians Annie Maunder (wife of Edward Maunder) and Agnes Clerke in 1894. They noticed these lack of sunspots apparently coincided with an absence of terrestrial auroras.
This low sunspot activity from 1645 to 1715 was named “The Maunder Minimum” from a paper written by American astronomer John A. Eddy in 1976 using the works of British astronomer Edward Maunder and Gustav Sporer.
I was “elmered” back in the 1970’s from hams who used to talk about how great the DX was in the 1960’s. And we’ve had some pretty good years for DX in the 1980’s and 1990s. I’m still working some pretty good DX these days, just not as often as I remember a few years ago. Are we in for another Maunder Minimum? Are we headed towards some colder winters?