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The data published in the VO can also be accessed using a web browser at https://vo.astron.nl. The web interface can be used to perform simple queries. The power of the VO lies in the fact that several applications exist that can interact with the standards we offer. In the architecture, there is a distinction between services and tables. A service is an entity that takes user input and provides a table as output. The tables themselves are the entities that actually hold the data. Tables can also be queried directly, for instance using ADQL. The colomns In the following table, we list the services for accessing data collections in the ASTRON VO. The columns of the table are:

Service name

The (human-readable) name of the service

TypeThe type of this service. Serrvices of type system are not coupled to specific data collections. The services that provide access to data are either of type image or cube. The image cutout services also offer images, but those are cutouts as define above. Finally there are catalogues which are either catalogues of astrophysical objects, or catalogues which tabulate the properties of the raw data files, that can be used to request them for download (in the Apertif DR1 case).
Table nameName of the table in the TAP service, or N/A for services that are not directly querying a table.
Service descriptionHuman-readable description of the service
Link to col. descsLink to the service info page in DACHS. For services that relate to a table (i.e. anything but the system services), this will contain three tables listing columns. The first table shows the input fields, which are the fields that can be used to query the service (typically those are RA, DEC and search radius). The next table shows the default output of a query, which is the subset of the table that has a verbosity of 20 or less. The third table shows all the columns present in the data table, including the ones with verbosity levels higher than 20. In the examples we will show how to access those columns. The table columns on the service info page show the column name (i.e. the term to query on using ADQL), the table header (e,g. when querying on DACHS this ends up as the table header for a column), a human-readable description, the unit of the data in this field, and the Unified Content Descriptor (UCD) which is a machine-readable definition of the data in the column. The goal of a UCD is to make sure that clients know how to handle the data in the column. For the average user those are probably not too relevant.

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This web interface provides a page on which all the collections present in the registry are listed.

Service nameTypeTable nameService descriptionService info
ADQL QuerysystemN/AThis provides a form that can be used to perform ADQL queries and get results in different formats.info (no columns)
LBCS Calibrator Searchcataloguelbcs.mainCatalog of calibrators from the Long-Baseline Calibrator Survey (LBCS).info
LoLSS - Image Cutout Serviceimage cutoutlolss.mosaicCutouts from the images of the LOFAR LBA Sky Survey (LoLSS).
info
LoLSS source catalogcataloguelolss.source_catalogSource catalogue of the LOFAR LBA Sky Survey (LoLSS).info
LoTSS-DR1 Cross-Matched Source Cataloguecatalogue

hetdex.main_merged

Catalogue of radio sources from the Lofar Two-metre Sky Survey First Data Release (LoTSS-DR1) that have been cross-matched with an optical or infrared counterpart.info
LoTSS-DR1 Image Archiveimagehetdex.hetdex_imagesImages of the Lofar Two-metre Sky Survey First Data Release (LoTSS-DR1).info
LoTSS-DR1 Image Cutout Serviceimage cutouthetdex.hetdex_imagesCutouts from the images of the Lofar Two-metre Sky Survey First Data Release (LoTSS-DR1).info
LoTSS-DR1 Raw Radio Catalogue Cone Searchcataloguehetdex.mainCatalogue of radio sources from the Lofar Two-metre Sky Survey First Data Release (LoTSS-DR1).
info
LoTSS-PDR Image Archiveimagelofartier1.img_mainImages of the Lofar Two-metre Sky Survey Preliminary Data Release (LoTSS-PDR).info
LoTSS-PDR Image Cutout Serviceimage cutoutlofartier1.img_mainCutouts from the images of the Lofar Two-metre Sky Survey Preliminary Data Release (LoTSS-PDR).info
LoTSS-PDR Source Cataloguecataloguelofartier1.mainCatalogue of radio sources from the Lofar Two-metre Sky Survey Preliminary Data Release (LoTSS-PDR).info
M) Apertif DR1 - Continuum imagesimageapertif_dr1.continuum_imagesContinuum images of the Apertif First Data Release (Apertif DR1).info
M) Apertif DR1 - HI spectral cubescubeapertif_dr1.spectral_cubesHI spectral cubes of the Apertif First Data Release (Apertif DR1).info
M) Apertif DR1 - Polarization images and cubesimage/cubeapertif_dr1.pol_cubesStokes V image and Stokes Q and U cubes of the Apertif First Data Release (Apertif DR1).info
MSSS Verification Field Imagesimagemvf.msssvf_img_mainBoth LBA and HBA images from the Multifrequency Snapshot Sky Survey (MSSS) verification field.
info
MSSS Verification Field Sourcescataloguemvf.mainUnified source catalogue from the Multifrequency Snapshot Sky Survey (MSSS) verification field.info
S) Apertif DR1 - Field calibrated visibilitiescatalogueapertif_dr1.calibrated_visibilitiesCatalogue of the properties from the calibrated visibilities of the fields from the Apertif First Data Release (Apertif DR1).info
S) Apertif DR1 - Field raw visibilitiescatalogueapertif_dr1.raw_visibilitiesCatalogue of the properties from the raw visibilities of the fields from the from the Apertif First Data Release (Apertif DR1).info
S) Apertif DR1 - Flux calibrator raw visibilitiescatalogueapertif_dr1.flux_cal_visibilitiesCatalogue of the properties from the calibrated visibilities of the flux calibrators from the Apertif First Data Release (Apertif DR1).info
S) Apertif DR1 - Pol. calibrator raw visibilitiescatalogueapertif_dr1.pol_cal_visibilitiesCatalogue of the properties from the calibrated visibilities of the polarisation calibrators from the Apertif First Data Release (Apertif DR1).info
SAURON HI Survey Imagesimagesauron.mom0Images of the SAURON WSRT HI Survey.info
SAURON HI Survey Velocity Fieldsimagesauron.mainVelocity field images of the SAURON WSRT HI Survey.info
TGSSADR Image Archiveimagetgssadr.img_mainImages of the TIFR GMRT Sky Survey Alternative Data Release (TGSS ADR).info
TGSSADR Image Cutout Serviceimage cutouttgssadr.img_mainCutouts from the images of the TIFR GMRT Sky Survey Alternative Data Release (TGSS ADR).info
TGSSADR Source Cataloguecataloguetgssadr.mainCatalogue of the radio sources in the TIFR GMRT Sky Survey Alternative Data Release (TGSS ADR).info
The VO @ ASTRON TAP servicesystem

N/A

(info only): description on how to access the tables using the TAP protocol.info (no columns)
Apertif DR1 beam cubes (table only, no service)
apertif_dr1.beam_cubesBeam cubes from the Apertif First Data Release (Apertif DR1), no connected service but accessible via TAP and linked from the other Apertif DR1 tables through DataLink.N/A

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