Wed, 04/19/2023 - 00:18
Of likely interest to this group is a recent article in Solar Physics (V. 298, Issue 3) titled "Recalibration of the Sunspot-Number: Status Report." The article describes differences in observations experienced by solar observers and the challenges of reconstructing historical sunspot data. It's a good read that offers a brief overview of the history of Sun-watching.
Find the abstract and article at https://link.springer.com/article/10.1007/s11207-023-02136-3?utm_source=toc&utm_medium=email&utm_campaign=toc_11207_298_3&utm_content=etoc_springer_20230401
Take a look at the January 2023 Solar Bulletin: https://www.aavso.org/sites/default/files/solar_bulletin/AAVSO_SB_2023_01.pdf
It has a reference to what you are talking about.