No. 213, "The 1859 Space Weather Event Revisited," by Ed Cliver: assessing the greatest space-weather events over the centuries. See

See http://sprg.ssl.berkeley.edu/~tohban/wiki/index.php/RHESSI_Science_Nuggets .

Older Nuggets are also available at
We publish these at roughly two-week intervals and welcome contributions, which should be related, at least loosely, to RHESSI science.