Table 2.
Ca II K datasets analysed in this study.
| Observatory | Acronym | Detector | Instrument | Period | Images | WL | SW | Pixel scale | Refs. | Figs. |
|---|---|---|---|---|---|---|---|---|---|---|
| [Å] | [Å] | [″/pixel] | ||||||||
| Baikal | Ba | CCD | Filter | 2004–2019 | 789 | 3933.7 | 1.2 | 2.7 | 1 | 6 |
| Big Bear | BB | CCD | Filter | 1982–2006 | 5026 | 3933.7 | 3.2, 1.5 (a) | 4.2, 2.4 (b) | 2 | 8 |
| Brussels | Br | CCD | Filter | 2012–2019 | 13248 | 3933.7 | 2.7 | 1.0 | 3 | 6 |
| Calern | CL | CCD | Filter | 2011–2019 | 1501 | 3933.7 | 7 | 1.0 | 4 | 6 |
| Kanzelhöhe | Ka | CCD | Filter | 2012–2019 | 4146 | 3933.7 | 3.0 | 1.0 | 5 | 8 |
| Mauna Loa PSPT | MLW | CCD | Filter | 2004–2015 | 9552 | 3936.3 | 1.0 | 1.0 | 6 | 7 |
| Mees | MS | CCD | Filter | 1988–1998 | 1513 | 3933.7 | 0.3 (c) | 5.5 | 7 | 6 |
| Meudon | MD1 | Plate/CCD (d) | SHG | 1978–2019 | 11916 | 3933.7 | 0.15, 0.09 (e) | 2.2, 1.5, 1.1 (f) | 8 | 10 |
| .... | MDW | CCD | SHG | 2002–2018 | 4481 | 3932.3 | 0.15 | 1.5 | 8 | 7 |
| Mount Wilson | MW | Plate | SHG | 1978–1985 | 2413 | 3933.7 | 0.2 | 2.9 | 9 | 10 |
| Rome PSPT | RP | CCD | Filter | 1996–2019 | 3337 | 3933.7 | 2.5 | 2.0 | 10 | 2 |
| San Fernando CFDT2 | SF | CCD | Filter | 1992–2013 | 4061 | 3933.7 | 9 | 2.6 | 11 | 6 |
| Teide ChroTel | Te | CCD | Filter | 2009–2019 | 1708 | 3933.7 | 0.3 | 1.0 | 12 | 6 |
Notes. Columns are: name of the observatory, abbreviation used in this study to refer to this dataset, type of detector, type of instrument, period of observations, total number of analysed images, central wavelength and spectral width of the spectrograph or filter, average pixel scale of the images, the bibliography entry, and the figure number in this paper showing the reconstructed TSI series with that dataset.
The two values correspond to the period before and after 10 September 1996, when the filter was changed.
The two values correspond to the period before and after 08 November 1995, when the CCD camera was upgraded.
This dataset comprises observations taken with an adjustable Lyot filter, and the main settings for bandwidth and offset in the central wavelength should be 0.3 Å and 0 Å, respectively. However, it is likely that it includes observations with the following settings too: [1.2, 0] Å, [0.3, −0.6] Å, [0.6, −0.6] Å for bandwidth and central wavelength combinations, respectively.
The observations were stored on photographic plates up to 27 September 2002, while observations with a CCD camera started on 13 May 2002.
The values refer to the periods [01 January 1978–14 June 2017] and [14 June 2017–31 December 2019].
The values refer to the periods [01 January 1978–27 September 2002], [28 September 2002–14 June 2017], and [15 June 2017–31 December 2019].
References. (1) Golovko et al. (2002); (2) Naqvi et al. (2010); (3) http://www.sidc.be/uset/; (4) Meftah et al. (2018); (5) Hirtenfellner-Polanec et al. (2011); (6) Rast et al. (2008); (7) http://kopiko.ifa.hawaii.edu/Reference/KLINE/; (8) Malherbe & Dalmasse (2019); (9) Lefebvre et al. (2005); (10) Ermolli et al. (2007); (11) Chapman et al. (1997); (12) Bethge et al. (2011).
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