How sunspots were observed “back then”?
From NASA...
The Sunspot Cycle
(Updated 2009/12/08)
Sunspot Numbers
In 1610, shortly after viewing the sun with his new telescope, Galileo Galilei (or was it Thomas Harriot?) made the first European observations of Sunspots. Continuous daily observations were started at the Zurich Observatory in 1849 and earlier observations have been used to extend the records back to 1610. The sunspot number is calculated by first counting the number of sunspot groups and then the number of individual sunspots.
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It is a treasure trove of knowledge, and we can always count on someone to have a vast arsenal of information at their disposal to build up the defenses we need to fight the good fight and shine the light of truth on an ignorant world.
Thanks for all the graphs and info ST.