The equinox in pre-hispanic canary islands

We report on the discovery of six possible equinoctial markers in some of the most important archaeological sites at four islands of the Canarian archipelago (Gran Canaria, Lanzarote, Fuerteventura, and Tenerife). The large fraction of equinoctial markers over the total number of sites with well defined astronomical alignments found is very high, indicating the high probability that the equinox or a date near it could be important in the calendar or ritual of the ancient islanders. We discuss the most likely astronomical target of this markers (astronomical equinox or half-way point in time between both solstices). Although the problem is not settled definitively, several clues favor the second possibility.