SVOCat Documentation

Version 2.01, October 2020, author: Carlos Rodrigo

1. Introduction
2. Download
    2.1. Extract
    2.2. Permissions
3. The files
4. Example
5. Configure
    5.1. First
    5.2. Project
    5.3. Mysql
    5.4. Web
    5.5. VO options
    5.6. Fields
    5.7. Photometry
    5.8. Search Opts.
    5.9. File Paths
    5.10. Scripts
    5.11. Registry
    5.12. Spectra
    5.13. Links
    5.14. References
6. Web Design
    6.1. style.css
    6.2. Colors
    6.3. header.php
    6.4. footer.php
7. Extra tips
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[First][Project][Mysql][Web][VO options][Fields][Photometry][Search Opts.][File Paths][Scripts][Registry][Spectra][Links][References]

VO curation

Virtual Observatory services are usually services that respond to special http queries with a document in a particular XML format named VOTable.

In these VOTables it is important to include information about the origin of the data, authors, etc. In the configuration application a short explanation of the meaning of these fields has been given. For a better explanation you can take a look to the SSAP VO Standard (sections and mainly).

These fields will be used in the metadata header of all the VO query responses for this service. If, for instance, you take a look to:

(where, remember, should be the main URL that corresponds to your installation)

in the first lines you will see a series of PARAMS giving the information that we have written above.

Given that these values must be included in XML responses like the ones above and that XML has some restrictions about it, please, try to use plain text here (no html tags, no & symbols...).

ConeSearch options

ConeSearch is a very simple protocol that is used in the Virtual Observatory for giving information about astronomical catalogues. You could want to take a look to the Simple Cone Search IVOA specification for more details (it is a very simple protocol, so it is a good point to start if this is the first time that you read a VO 'standard' document).

As a summary, the main idea of this protocol is that it allows to search for objects in a catalogue around a given point (specified by its RA and DEC coordinates in decimal degrees) and within a Search Radius (SR) also in decimal degrees.

Thus, a typical ConeSearch query would be something like:


meaning that we want objects in the catalogue around RA=1.01, DEC=10.04 (degrees) and within a radius of 0.1 degrees.

The answer will be a VOTable (special VO document in XML format) containing the info in the catalogue for objects that match the conditions.

In the version of ConeSearch implemented by SVOCat we have included additional options that allow to restrict the queries using other catalogue columns if you want to allow it. We will explain that later.

In this configuration section we only ask for very simple information:

  • 'MaxSR': the maximum Search Radius (in decimal degrees) that is allowed for queries. If your catalogue is small you don't need to specify this (leave it blank or write 180 here). But if your catalogue is big you will probably want to restrict queries to small radius so that queries are faster and the list of results is not too large.
  • 'Description': A simple description of the catalogue that will be included in all the VOTables generated by the service (See the example above). You can not use html here. Use plain text.

SSAP options

SSAP (Simple Spectra Access Protocol) is a VO protocol designed to offer information about available spectra. You could want to read the IVO SSA standard for more information about it.

If your catalogue does not include spectra you just won't active SSAP.

If you have spectra to offer and you want to activate SSAP you need also to choose one of the catalogue fields as 'object unique ID' (after you configure the fields) and you will also have to configure how to access your spectra and their properties in the Spectra section later.

VO Availability

VO applications can query a VO service about its availability. If you configure it here as "Not available" those applications that query for this information will probably not query your service for data. But take into account that this won't make you service really unavailable.

In principle, we recommend you to let this configuration option as 'Available' and don't worry about this.

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