Bechet, Sabrina

Invited talk presented at Joint Symposium of Space Climate Symposium 9 and ISEE Symposium - Nagoya on 2024-10-01

Abstract: Sunspot drawings are a unique source of data to retrieve long-term information on the evolution of the solar cycle. In this talk we will discuss major challenges concerning the analysis of sunspot drawings, and in particular the need of a general tool available in the solar physics community. Currently there is a lack of homogeneity among the analysed data, and some sunspot drawing collections from all over the world are still not exploited to their full potential, because they are buried in archives, or not in machine readable format. The use of a standard tool for the parameters measurement would make it easier to analyse contemporary sunspot drawings, and especially to fill the inevitable gaps from a single observing station by merging homogeneous data. We will present our experience at the Royal Observatory of Belgium (ROB), with DigiSun, the in-house software developed for the measurement of sunspot drawings and for the construction of a sunspot catalogue for the local station USET. The software is multi-platform and can handle different drawing formats, which allows its application to collections from other observatories. A first successful international collaboration with the Specola Observatory in Locarno was initiated in 2019. In addition, DigiSun could be used to analyse historical drawings and extend the series of detailed solar parameters further back in the past.