Historical observations of STEVE

Abstract

Recent work by MacDonald et al. has highlighted the valuable work carried out by sky watchers and auroral enthusiasts in obtaining high-quality digital images of rare and unusual auroral structures. A feature of particular interest, which has been nicknamed "Steve", typically takes the form of a short-lived arch, beam, or narrow band of light in the sky. MacDonald et al. have established that the phenomenon is characterised by a range of optically visible low magnetic latitude structures associated with a strong subauroral ion drift. Respecting its nickname, they have dubbed the phenomenon STEVE, an acronym for Strong Thermal Emission Velocity Enhancement. Here, we draw attention to earlier observations of similar structures, showing that some previously unidentified atmospheric, meteoric or auroral "anomalies" can now be recognized as examples of "Steve", and therefore as part of a broad spectrum of occasional auroral features that may appear well below the region of magnetic latitudes represented by the traditional auroral oval. This highlights the contributions of "citizen scientists" dating back hundreds of years, and the importance of reassessing historical reports of rare auroral luminosities for a full understanding of the range of solar activity over millennia.