Extending the sunspot area series from Kodaikanal Solar Observatory

• DOI: 10.3389/fspas.2022.1019751
• Publication Date: 2022-10-25T07:25:45Z
• Authors: Bibhuti Kumar Jha; Manjunath Hegde; Aditya Priyadarshi; Sudip Mandal; B. Ravindra; Dipankar Banerjee
• Keywords: Sunspot; On board

Kodaikanal Solar Observatory (KoSO) possesses one of world's longest and homogeneous records sunspot observations that span more than a century (1904-2017). Interestingly, these (originally recorded in photographic plates/films) were taken with the same setup over this entire time period which makes data unique best suitable for long-term solar variability studies. A large part data, between 1921-2011, digitized earlier catalog containing detected parameters (e.g., area location) was published Mandal et al.(2017). In article, we extend by including new sets 1904-1921 2011-2017. To end, digitize calibrate datasets include resolving issue random image orientation. We fix comparing KoSO images co-temporal from Royal Greenwich Observatory. Following that, semi-automated detection automated umbra algorithm are implemented onto calibrated to detect sunspots umbra. Additionally, during updation, also filled gaps existing (1921-2011) virtue re-calibrating 'rouge' plates. This updated series covering nearly 115 years (1904-2017) being made available community will be source study long term Sun