<?xml version='1.0'?><?xml-stylesheet href='/static/xsl/oai.xsl' type='text/xsl'?><ri:Resource created="2026-04-09T08:30:00Z" status="active" updated="2026-04-10T15:23:43" xmlns:cs="http://www.ivoa.net/xml/ConeSearch/v1.0" xmlns:ri="http://www.ivoa.net/xml/RegistryInterface/v1.0" xmlns:vg="http://www.ivoa.net/xml/VORegistry/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/ConeSearch/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/ConeSearch-v1.1.xsd http://www.ivoa.net/xml/RegistryInterface/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/RegistryInterface-v1.0.xsd http://www.ivoa.net/xml/VORegistry/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/VORegistry-v1.0.xsd http://www.ivoa.net/xml/VOResource/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/VOResource-v1.1.xsd http://www.ivoa.net/xml/VODataService/v1.1 http://vo.ari.uni-heidelberg.de/docs/schemata/VODataService-v1.1.xsd" xsi:type="vs:CatalogService"><title>Apertif DR2 - Field calibrated visibilities</title><shortName>CalVis</shortName><identifier>ivo://astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities</identifier><curation><publisher>ASTRON</publisher><creator><name>Apertif Team</name></creator><date role="updated">2026-04-10T15:23:43</date><contact><name>Michael Sipior</name><address>Oude Hoogeveensedijk 4, 7991PD Dwingeloo, the Netherlands</address><email>vo@astron.nl</email></contact></curation><content><subject>HI line</subject><subject>radio</subject><description> Apertif is a phased-array feed system for the Westerbork Synthesis
Radio Telescope (WSRT), providing forty instantaneous beams over 300
MHz of bandwidth. A description of the second data release is to be
included here. This service queries the calibrated visibility
measurement sets. The calibrated visibility data, with
cross-calibration and self-calibration solutions applied, are
currently stored as an intermediate data product at full time and
spectral resolution. These are stored on tape with the raw data and
are not immediately available for download. The data release
documentation should be consulted for up-to-date information on how to
access the data.</description><source format="bibcode">2022A&amp;A...667A..38A</source><referenceURL>https://vo.astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities/info</referenceURL><type>Survey</type><contentLevel>Research</contentLevel><relationship><relationshipType>served-by</relationshipType><relatedResource ivo-id="ivo://astron.nl/tap">The VO @ ASTRON TAP service</relatedResource></relationship></content><rights rightsURI="http://creativecommons.org/licenses/by/3.0/">Licensed under CC-BY</rights><capability standardID="ivo://ivoa.net/std/ConeSearch" xsi:type="cs:ConeSearch"><interface role="std" xsi:type="vs:ParamHTTP"><accessURL use="base">https://vo.astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities/scs.xml?</accessURL><queryType>GET</queryType><resultType>application/x-votable+xml</resultType><param std="true"><name>RA</name><description>Right Ascension (ICRS decimal)</description><unit>deg</unit><ucd>pos.eq.ra</ucd><dataType>real</dataType></param><param std="true"><name>DEC</name><description>Declination (ICRS decimal)</description><unit>deg</unit><ucd>pos.eq.dec</ucd><dataType>real</dataType></param><param std="true"><name>SR</name><description>Search radius</description><unit>deg</unit><dataType>real</dataType></param><param std="false"><name>target</name><description>Name of the field</description><ucd>meta.id</ucd><dataType arraysize="*">char</dataType></param><param std="false"><name>beam</name><description>Beam number</description><ucd>meta.id</ucd><dataType>integer</dataType></param><param std="false"><name>task_id</name><description>Observation id</description><ucd>meta.id</ucd><dataType arraysize="*">char</dataType></param></interface><maxSR>180</maxSR><maxRecords>100000</maxRecords><verbosity>true</verbosity><testQuery><ra>342.1</ra><dec>33.9</dec><sr>0.001</sr></testQuery></capability><capability standardID="ivo://ivoa.net/std/VOSI#availability"><interface role="std" xsi:type="vs:ParamHTTP"><accessURL use="full">https://vo.astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities/availability</accessURL></interface></capability><capability standardID="ivo://ivoa.net/std/VOSI#capabilities"><interface role="std" xsi:type="vs:ParamHTTP"><accessURL use="full">https://vo.astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities/capabilities</accessURL></interface></capability><capability standardID="ivo://ivoa.net/std/VOSI#tables"><interface role="std" xsi:type="vs:ParamHTTP"><accessURL use="full">https://vo.astron.nl/apertif_dr2/q/apertif_dr2_calibrated_visibilities/tableMetadata</accessURL></interface></capability><capability standardID="ivo://ivoa.net/std/TAP#aux"><interface role="std" version="1.1" xsi:type="vs:ParamHTTP"><accessURL use="base">https://vo.astron.nl/tap</accessURL></interface></capability><facility>WSRT</facility><instrument>Apertif</instrument><coverage><waveband>Radio</waveband></coverage><tableset><schema><name>apertif_dr2</name><title>Apertif DR-2</title><table><name>apertif_dr2.calibrated_visibilities</name><column><name>target</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>ra</name><unit>deg</unit><ucd>pos.eq.ra;meta.main</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>indexed</flag><flag>nullable</flag></column><column><name>dec</name><unit>deg</unit><ucd>pos.eq.dec;meta.main</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>indexed</flag><flag>nullable</flag></column><column><name>beam</name><ucd>meta.id</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>fov</name><unit>deg</unit><ucd>phys.angSize;instr.fov</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>central_frequency</name><unit>MHz</unit><ucd>em.frequency</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>n_channels</name><ucd>meta.number</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>bandwidth</name><unit>MHz</unit><ucd>em.frequency</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>t_min</name><ucd>time.start;obs.exposure</ucd><dataType arraysize="19" extendedType="timestamp" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>t_max</name><ucd>time.end;obs.exposure</ucd><dataType arraysize="19" extendedType="timestamp" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>duration</name><unit>h</unit><ucd>time.duration;obs.exposure</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>task_id</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>obsid</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>dataproduct_type</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>dataproduct_subtype</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>product_key</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>equinox</name><ucd>meta.text</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>quality</name><ucd>meta.id</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>pub_did</name><description>Dataset identifier assigned by the publisher</description><ucd>meta.id;meta.main</ucd><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column><column><name>accref</name><description>Access url for the data</description><utype>Access.Reference</utype><dataType arraysize="*" xsi:type="vs:VOTableType">char</dataType><flag>nullable</flag></column></table></schema></tableset></ri:Resource>