The Great Aurora of January 1770 observed in Spain

The Great Aurora of January 1770 observed in Spain

V. M. S. Carrasco, E. Aragonès, J. Ordaz, J. M. Vaquero, J. M. Vaquero

An analysis is made of the records made by Spanishobservers of a notable aurora on 18 January 1770 in order to study thecharacteristics of this event. The records indicate that the phenomenon wasobserved in both continental and insular territories of Spain, in particularat San Cristóbal de la Laguna, Cádiz, Córdoba, Badajoz,Valencia, Castellón, Madrid, Barcelona, and Gerri de la Sal. The mostequatorward observational site was San Cristóbal de la Laguna(28.48° N, 16.32° W) in the Canary Islands. In general,the descriptions put its duration from sunset to midnight, but the observersfrom Córdoba and Madrid report the aurora as being visible during thelast hours of the night, and it was even observed the following day atCastellón. All the observers described the aurora as red in colour,while white and ash colours were also reported at Córdoba and Gerri dela Sal. The brightness and shape of auroral display changed over time.Calculations of the geomagnetic latitudes of the observation locations gaveSan Cristóbal de la Laguna as the southernmost (26° N) andGerri de la Sal the northernmost (35° N) and indicate this aurorawas observed over a wide range of abnormally low latitudes for such aphenomenon. Solar activity around the event was high, with the astronomerHorrebow registering 10 sunspot groups on that date (18 January 1770).

2018

10.5194/hgss-9-133-2018

History of Geo- and Space Sciences

Copernicus Publications

Science, Geology, Physics, Geophysics. Cosmic physics, Dynamic and structural geology