{"paper":{"title":"The potential of Ca II K observations for solar activity and variability studies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.SR","authors_text":"Ilaria Ermolli, Natalie A. Krivova, Sami K. Solanki, Theodosios Chatzistergos","submitted_at":"2018-05-11T16:40:53Z","abstract_excerpt":"Several observatories around the globe started regular full-disc imaging of the solar atmosphere in the Ca II K line in the early decades of the 20th century. These observations are continued today at a few sites with either old spectroheliographs or modern telescopes equipped with narrow-band filters. The Ca II K time series are unique in representing long-term variations of the Sun's chromospheric magnetic field. However, meaningful results from their analysis require accurate processing of the available data and robust merging of the information stored in different archives. This paper prov"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1805.04483","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}