Table 1.
Ca II K datasets analysed in this study.
| Observatory | Acronym | Detector | Instrument | Period | Images | SW | Pixel scale | Ref. |
|---|---|---|---|---|---|---|---|---|
| [Å] | [″/pixel] | |||||||
| Arcetri(a) | Ar | Plate | SHG | 1931–1974 | 4871 | 0.3 | 2.5 | 1 |
| Baikal | Ba | CCD | Filter | 2004–2019 | 846 | 1.2 | 2.7 | 2 |
| Big Bear | BB | CCD | Filter | 1982–2006 | 5027 | 3.2, 1.5(b) | 4.2, 2.4(c) | 3 |
| Brussels | Br | CCD | Filter | 2012–2019 | 14699 | 2.7 | 1.0 | 4 |
| Calern | CL | CCD | Filter | 2011–2019 | 1560 | 7 | 1.0 | 5 |
| Catania | CT | Plate | SHG | 1908–1977 | 1008 | – | 1.1–5 | 6 |
| Coimbra | Co | Plate/CCD(d) | SHG | 1925–2019 | 19758 | 0.16 | 2.2 | 7 |
| Kanzelhöhe | Ka | CCD | Filter | 2010–2019 | 8550 | 3.0 | 1.0 | 8 |
| Kenwood | Ke | Plate | SHG | 1892 | 5 | – | 3.1 | 9 |
| Kharkiv | Kh | Plate/CCD(e) | SHG | 1952–2019 | 564 | 3.0 | 3.3 | 10 |
| Kislovodsk | Ki | Plate/CCD(f) | SHG | 1960–2019 | 9738 | – | 1.3, 2.3(f) | 11 |
| Kodaikanal(a) | Ko | Plate | SHG | 1904–2007 | 45047 | 0.5 | 0.9 | 12 |
| Kodaikanal Twin | KT | CCD | Filter | 2008–2013 | 3059 | 1.2 | 1.2 | 13 |
| Kodaikanal WARM | KW | CCD | Filter | 2017–2019 | 585 | 1.0 | 2.4 | 14 |
| Kyoto | Ky | Plate | SHG | 1928–1969 | 3119 | 0.74 | 2.0 | 15 |
| Manila | Ma | Plate | SHG | 1968–1978 | 162 | 0.5 | 1.2 | 16 |
| Mauna Loa PSPT | ML | CCD | Filter | 1998–2015 | 31933 | 2.7 | 1.0 | 17 |
| McMath-Hulbert(a) | MM | Plate | SHG | 1948–1979 | 4932 | 0.1 | 3.1 | 18 |
| Mees | MS | CCD | Filter | 1982–1998 | 1519 | 1.2 | 5.5 | 19 |
| Meudon(a) | MD1 | Plate/CCD(g) | SHG | 1893–2019 | 20117 | 0.15, 0.09(h) | 2.2, 1.5, 1.1(i) | 20 |
| Meudon | MD2 | CCD | Filter | 2007–2014 | 1519 | 1.4 | 0.9 | 21 |
| Mitaka(a) | Mi1 | Plate | SHG | 1917–1974 | 4193 | 0.5 | 0.9, 0.7(j) | 22 |
| Mitaka | Mi2 | CCD | Filter | 2015–2019 | 897 | 4.5 | 1.0 | 23 |
| Mount Wilson(a) | MW | Plate | SHG | 1915–1985 | 39545 | 0.2 | 2.9 | 24 |
| Pic du Midi | PM | CCD | Filter | 2007–2019 | 3794 | 2.5 | 1.2 | 25 |
| PICARD/SODISM | PS | CCD | Filter | 2010–2014 | 1218 | 7 | 1 | 26 |
| Rome Monte Mario | Ro | Plate | Filter | 1964–1979 | 5826 | 0.3 | 5.0 | 27 |
| Rome PSPT(a) | RP1 | CCD | Filter | 1996–2019 | 3449 | 2.5 | 2.0(k) | 28 |
| Rome PSPT | RP2 | CCD | Filter | 2008–2019 | 1298 | 1.0 | 2.0(k) | 28 |
| Sacramento Peak | SP | Plate | SHG | 1960–2002 | 7750 | 0.5 | 1.2 | 29 |
| San Fernando CFDT1 | SF1 | CCD | Filter | 1988–2015 | 4986 | 9 | 5.1 | 30 |
| San Fernando CFDT2 | SF2 | CCD | Filter | 1992–2013 | 4065 | 9 | 2.6 | 30 |
| Schauinsland(a) | Sc | Plate | SHG | 1958–1965 | 18 | – | 1.7, 2.6(l) | 31 |
| Teide ChroTel | Te | CCD | Filter | 2009–2019 | 1843 | 0.3 | 1.0 | 32 |
| Upice | UP | CCD | Filter | 1998–2019 | 3234 | 1.6 | 4.0, 2.4(m) | 33 |
| Valašské Meziřičí | VM | CCD | Filter | 2011–2018 | 318 | 2.4 | 1.8 | 34 |
| Wendelstein(a) | WS | Plate | SHG | 1947–1977 | 422 | – | 1.7, 2.6(l) | 31 |
| Yerkes | YR | Plate | SHG | 1903–1907 | 7 | – | 2.4 | 35 |
Notes. Columns are: name of the observatory, abbreviation used in this study, type of detector, type of instrument, period of observations, total number of images (including multiple images on a single day when available) analysed in this study, spectral width of the spectrograph/filter, average pixel scale of the images, and the bibliography entry.
These archives were considered in Paper II, although in the case of the Ko data the earlier 8-bit digitisation was used.
The two values correspond to the period before and after 08/11/1995, when the CCD camera was upgraded.
The CCD camera was installed in January 2007, but observations were stored on photographic plates up to December 2007.
The observations were stored on photographic plates up to 27/09/2002, while observations with a CCD camera started on 13/05/2002.
The values refer to the periods [24/10/1893–27/09/2002], [28/09/2002–14/06/2017], and since 15/06/2017.
These data derive from two digitisations and the two values correspond to the earlier and more recent digitisation, respectively. See Chatzistergos et al. (2019b) for more information.
The pixel scale is for the resized images to match the seeing conditions of the observing location.
These data were stored in TIFF and JPG files with different spatial resolution, the values correspond to the TIFF and JPG files, respectively.
The two values correspond to the period before and after 01/01/2018, when the CCD camera was upgraded.
(1) Ermolli et al. (2009a); (2) Golovko et al. (2002); (3) Naqvi et al. (2010); (4) http://www.sidc.be/uset/; (5) Meftah et al. (2018); (6) Zuccarello et al. (2011); (7) Garcia et al. (2011); (8) Hirtenfellner-Polanec et al. (2011); (9) Hale (1893); (10) Belkina et al. (1996); (11) Tlatov et al. (2015); (12) Priyal et al. (2014); (13) Singh & Ravindra (2012); (14) Pruthvi & Ramesh (2015); (15) Kitai et al. (2013); (16) Miller (1965); (17) Rast et al. (2008); (18) Mohler & Dodson (1968); (19) http://kopiko.ifa.hawaii.edu/; (20) Malherbe & Dalmasse (2019); (21) http://bass2000.obspm.fr/data_guide.php; (22) Hanaoka (2013); (23) Hanaoka & Solar Observatory of NAOJ (2016); (24) Lefebvre et al. (2005); (25) Koechlin et al. (2019); (26) Meftah et al. (2014); (27) Chatzistergos et al. (2019a); (28) Ermolli et al. (2007); (29) Tlatov et al. (2009); (30) Chapman et al. (1997); (31) Wöhl (2005); (32) Bethge et al. (2011); (33) Klimeš et al. (1999); (34) Lenza et al. (2014); (35) Hale & Ellerman (1903).
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