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<ri:Resource created="2026-08-13T10:04:56Z" status="active" updated="2026-08-13T09:05:24Z" version="1.2" xmlns:ri="http://www.ivoa.net/xml/RegistryInterface/v1.0" xmlns:vr="http://www.ivoa.net/xml/VOResource/v1.0" xmlns:vs="http://www.ivoa.net/xml/VODataService/v1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ivoa.net/xml/VOResource/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/VOResource.xsd http://www.ivoa.net/xml/VODataService/v1.1 http://vo.ari.uni-heidelberg.de/docs/schemata/VODataService.xsd" xsi:type="vs:CatalogService"><title>PyMoST sunspot data</title><shortName>J/other/SoPh/301</shortName><identifier>ivo://CDS.VizieR/J/other/SoPh/301.2</identifier><curation><publisher ivo-id="ivo://CDS">CDS</publisher><creator><name>Grangeiro C.D.</name></creator><creator><name>Duarte T.S.S.</name></creator><creator><name>da Costa J.S.</name></creator><creator><name>Coelho H.R.,de Oliveira G.F Jr</name></creator><creator><name>do Nasciemnto J.-D. Jr</name></creator><date role="Updated">2026-08-13T09:05:24Z</date><date role="Created">2026-08-13T10:04:56Z</date><contact><name>CDS support team</name><address>CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France</address><email>cds-question@unistra.fr</email></contact></curation><content><subject>the-sun</subject><description>In this study, we report on the processing and analysis of around 9700 images of the solar disk, obtained from the SOHO and SDO satellites, available in the Helioviewer database. Using our own code, PyMoST (Python Morphological Sunspot Tracker), which employs a mathematical morphology technique, we were able to automatically track and analyze approximately 50000 sunspots in these images, covering the period from January 1, 1998 to July 31, 2024. By using PyMoST we were able to obtain the distribution of the number of spots as a function of solar latitude and time, accurately reproducing solar cycles 23, 24 and the current phase of solar cycle 25, in agreement with the literature. In addition, our code was also able to determine the areas and number of sunspots, showing excellent correlation with the results reported by the Royal Greenwich Observatory (RGO), Kodaikanal Solar Observatory (KSO) and the International Sunspot Number - Solar Influences Data Analysis Center (SIDIC), thus consolidating the efficiency of our tool and its importance for the investigation of solar magnetic activity.</description><source format="bibcode">2026SoPh..301....2G</source><referenceURL>https://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/SoPh/301.2</referenceURL><type>Catalog</type><contentLevel>Research</contentLevel><relationship><relationshipType>IsServedBy</relationshipType><relatedResource ivo-id="ivo://CDS.VizieR/TAP">TAP VizieR generic service</relatedResource></relationship></content><rights>https://cds.unistra.fr/vizier-org/licences_vizier.html</rights><capability><interface xsi:type="vr:WebBrowser"><accessURL use="full">https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/SoPh/301.2</accessURL><mirrorURL title="VizieR at IUCAA: Pune, India">https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/SoPh/301.2</mirrorURL><mirrorURL title="VizieR at SAAO: SAAO, South Africa">http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/SoPh/301.2</mirrorURL></interface></capability><capability><interface xsi:type="vs:ParamHTTP"><accessURL use="base">https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/SoPh/301.2</accessURL><mirrorURL title="VizieR at IUCAA: Pune, India">https://vizier.iucaa.in/viz-bin/votable?-source=J/other/SoPh/301.2</mirrorURL><mirrorURL title="VizieR at SAAO: SAAO, South Africa">http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/SoPh/301.2</mirrorURL><queryType>GET</queryType><resultType>text/xml+votable</resultType></interface></capability><capability standardID="ivo://ivoa.net/std/TAP#aux"><interface xsi:type="vs:ParamHTTP" role="std"><accessURL use="base">https://tapvizier.cds.unistra.fr/TAPVizieR/tap</accessURL></interface></capability><coverage><footprint ivo-id="ivo://ivoa.net/std/moc"/></coverage><tableset><schema><name>default</name><table><name>J/other/SoPh/301.2/sunspots</name><description>PyMoST latitude and sunspot area data</description><column><name>recno</name><description>Record number assigned by the VizieR team. Should Not be used for identification.</description><ucd>meta.record</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>Time</name><description>Observation date</description><ucd>time.epoch;obs</ucd><flag>nullable</flag><flag>indexed</flag></column><column><name>Lat</name><description>? Latitude</description><unit>deg</unit><ucd>pos.frame</ucd><dataType xsi:type="vs:VOTableType">double</dataType><flag>nullable</flag></column><column><name>Area</name><description>? Area in millionths of the Sun's visible hemisphere unit</description><ucd>phys.area</ucd><dataType xsi:type="vs:VOTableType">double</dataType><flag>nullable</flag></column></table><table><name>J/other/SoPh/301.2/groups</name><description>PyMoST data on number of groups</description><column><name>recno</name><description>Record number assigned by the VizieR team. Should Not be used for identification.</description><ucd>meta.record</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>Time</name><description>Observation date</description><ucd>time.epoch</ucd><flag>nullable</flag></column><column><name>Groups</name><description>Number of groups</description><ucd>meta.number</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column></table></schema></tableset></ri:Resource>