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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 of the table are:
Service name | The (human-readable) name of the service |
| Type | The 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 name | Name of the table in the TAP service, or N/A for services that are not directly querying a table. |
| Service description | Human-readable description of the service |
| Link to col. descs | Link 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. |
This web interface provides a page on which all the collections present in the registry are list
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