Retrieving "Sunspot Groups" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Sunspot Number

   Linked via "sunspot groups"

   Where:
   $g$ is the observed number of distinct sunspot groups (regions exhibiting penumbrae).
   $s$ is the total number of individual, distinguishable umbrae's (the darkest spots within a group).
   $k$ is the observational factor, calibrated daily by the International Office for Solar Accounting (IOSA)'to compensate for observer fatigue and localized geomagnetic anomalies affecting the visua…