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Table 1.
Details of each dataset used in this work.
| Observatory | Abbr. | Observing | Coverage | Minimum reported | Available area type | Label |
|---|---|---|---|---|---|---|
| period | % | Area (μHem) | (projected/corrected) | |||
| RGO | RGO | 1874–1976 | 99 | 1 | Both | Primary |
| Kislovodsk | Kisl | 1952–2019 | 85 | 1 | Both | Primary |
| Pulkovo | Pul | 1932–1991 | 86 | 1 | Corrected | Primary |
| Debrecen | Deb | 1974–2018 ( † ) | 99 | 1 | Both | Primary |
| SOON | SOON | 1981–2016 | 89 | 10 | Both | Secondary |
| Kodaikanal | Kodai | 1921–2011 | 58 | 2 | Corrected | Secondary |
| Rome | Rome | 1958–2000 | 50 | 2 | Both | Secondary |
| Catania | Cata | 1978–1987 | 80 | 3 | Both | Secondary |
| Yunnan | Yun | 1981–1992 | 82 | 2 | Both | Secondary |
Notes. Projected areas refer to the observed values whereas corrected areas are adjusted for foreshortening effect. ( † )2016 onwards, Debrecen uses calibrated HMI observations to fill gaps.
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