Temporal and Spatial Evolutions of a Large Sunspot Group and Great Auroral Storms Around the Carrington Event in 1859

The Carrington event is considered to be one of the most extreme space weather events in observational history within a series of magnetic storms caused by extreme interplanetary coronal mass ejections from a large and complex active region that emerged on the solar disk. In this article, we study the temporal and spatial evolutions of the source sunspot active region and visual aurorae and compare this storm with other extreme space weather events on the basis of their auroral spatial evolution. Sunspot drawings by Schwabe, Secchi, and Carrington describe the position and morphology of the source active region at that time. Visual auroral reports from the Russian Empire, Iberia, Ireland, Oceania, and Japan fill the spatial gap of auroral visibility and revise the time series of auroral visibility in middle to low magnetic latitudes. The reconstructed time series is compared with magnetic measurements and shows the correspondence between low‐latitude to mid‐latitude aurorae and the phase of magnetic storms. The spatial evolution of the auroral oval is compared with those of other extreme space weather events in 1872, 1909, 1921, and 1989 as well as their storm intensity and contextualizes the Carrington event, as one of the most extreme space weather events, but likely not unique. Plain Language Summary The Carrington event is considered to be one of the most extreme space weather events in observational history. In this article, we have studied the temporal and spatial evolutions of the source active region and visual low‐latitude aurorae. We have also compared this storm with other extreme space weather events on the basis of the spatial evolution. We have compared the available sunspot drawings to reconstruct the morphology and evolution of sunspot groups at that time. We have surveyed visual auroral reports in the Russian Empire, Ireland, Iberian Peninsula, Oceania, and Japan and fill the spatial gap of auroral visibility and revised its time series. We have compared this time series with magnetic measurements and shown the correspondence between low‐latitude to midlatitude aurorae and the phase of magnetic storms. We have compared the spatial evolution of the auroral oval with those of other extreme space weather events in 1872, 1909, 1921, and 1989 as well as their storm intensity and concluded that the Carrington event is one of the most extreme space weather events but is likely not unique. Key Points Original sunspot drawings during the 1859 storm