The long-term solar variability, as reconstructed from historical sources: Several case studies in the 17th -- 18th centuries

TL;DR

This paper reviews historical sunspot records from the 17th and 18th centuries, highlighting their importance for reconstructing long-term solar activity and discussing recent updates to these archival datasets.

Contribution

It provides a synthesis of recent archival investigations of historical sunspot data and emphasizes their role in understanding solar variability over centuries.

Findings

Updated active day fraction data for the Maunder Minimum

Revised positions of sunspot groups during the 17th-18th centuries

Archival datasets as foundational for solar activity reconstruction

Abstract

On a centennial timescale, solar activity was quantified based on records of instrumental sunspot observations. This article briefly discusses several aspects of the recent archival investigations of historical sunspot records in the 17th to 18th centuries. This article also reviews the recent updates for the active day fraction and positions of the reported sunspot groups of the Maunder Minimum to show their significance within the observational history. These archival investigations serve as base datasets for reconstructing solar activity.