Equivalence relations between the Cortie and Zurich sunspot group morphological classifications

Abstract

Catalogues of sunspots have been available with useful information about sunspots or sunspot groups for approximately the last 150 years. However, the task of merging these catalogues is not simple. In this paper, a method is suggested of converting the types of sunspot groups that were proposed by Cortie (1901) into the well-known Zurich types of sunspot groups. To achieve this, the sunspot catalogue of the Valencia University Observatory (from 1920 to 1928) was used in addition to the descriptions proposed by Cortie. To assess the quality of this conversion scheme, the Zurich type was computed from the Valencia catalogue, and the resulting contribution of each group type was compared to what can be found in other catalogues. The results show that the proposed scheme works well within the errors that are found in the different catalogues.

arXiv comment17 pages, 7 figures, 3 tables, accepted for publication in Solar Physics

References in corpus (8)

• Revisiting the Sunspot Number
• Historical Sunspot Observations: A Review
• Time Distributions of Large and Small Sunspot Groups Over Four Solar Cycles
• Sunspot Numbers and Areas from the Madrid Astronomical Observatory (1876-1986)
• Sunspot Count Periodicities in Different Zurich Sunspot Group Classes since 1986
• A Curious History of Sunspot Penumbrae
• Sunspot Catalogue of the Valencia Observatory (1920-1928)
• The Sunspot Catalogues of Carrington, Peters, and de la Rue: Quality Control and Machine-readable Versions

Cited by in corpus (3)

• Sunspot Catalogue of the Observatory of the University of Coimbra (1929-1941)
• Daniel Mögling's sunspot observations in 1626 - 1629: A manuscript reference for the solar activity before the Maunder Minimum
• A Sunspot Catalog for the Period 1952-1986 from Observations Made at the Madrid Astronomical Observatory