The VO is all about making data accessible to both scientists and the general public. It is, however, also a highly complex network of computers distributed all over the planet. Thus it may seem somewhat daunting at first. On this page, we try to smooth out the rough first steps.
There are many worked-out examples of work with the VO on the net. To get an idea what the VO is, these may be good starting points --
- Science use cases from EuroVO -- some of them were created in collaboration with GAVO.
- Examples and tutorials on how to find and analyze data and
- Common astronomical search tasks you can do with the VO prepared by the US NVO.
- VO use cases for outreach provided by EuroVO
Locating data and services
There are of the order of 10**4 data collections and services in the VO. Clearly, it is important to have some sort of inventory. In the VO, this is called the registry. There are many interfaces to searching in that registry out there. A recommended approach for browsing the registry is the Web Interface to the Relational, or short WIRR. This user interface lets you combine a number of search criteria like the waveband, the (astronomical) subject or the service type (e.g. cone search, image service, etc.) in an additive way.
For simple searches, you could also use the google-style full-text search form here:
Other interfaces include the US-VAO's Directory (google-like search for resources) and DataScope (locate resources by celestial position), as well as the Euro-VO registry that allows advanced queries using SQL.
New services are continuously being added to the VO, and existing services are being updated. To keep up to date, subscribe to the VO Fresh RSS feed. You can also follow us on Twitter or, preferably, on identi.ca.
Probably the most convenient way to use the registry may still be the VODesktop program mentioned in the next section, although it is starting to show signs of its age.
While quite a bit of the VO can be used with a plain web browser, in the end tools on your desktop are more powerful or just more convient (and some of them run in your browser). Here are some of the more common VO tools -- all of them freely downloadable, many of them available in source form.
- TOPCAT -- one of the most advanced tools to process and manipulate the VO's native data format, VOTables.
- STILTS -- a program that lets you do about all TOPCAT does, only scriptable and from the command line.
- Aladin -- an interactive sky atlas with advanced plotting facilities, written by the CDS. The standalone version has some significant advantages over the well-known applet (e.g., communication with other VO tools).
- VOSpec -- A tool to retrieve and analyze spectra, written by ESA
- Specview -- Another tool to work with spectra, written by STScI. Compared to VOSpec, it strives for more compatibility with legacy data.
- SPLAT-VO -- A graphical tool for displaying, comparing, modifying and analysing astronomical spectra stored in various data formats. The project is now being developed by GAVO. Beta versions of the most recent improvements are avilable at the GAVO SPLAT-VO project page.
- tapsh -- a command line interface to the VO's database query protocol, TAP.
- VODesktop -- an application allowing you to locate and query VO services, unfortunately not maintained anymore. A similar functionality is provided by running WIRR in combination with TOPCAT.
- AstroStat -- a tool for both simple and sophisticated statistical routines on large datasets, based on the statistical computing package called R.
Publishing your data in the VO
Your data is too valuable to let it become forgotten -- publish it to the VO! While there is quite a bit of software that can help you set up your own VO service (see, e.g., EuroVO's developer page), it is probably more convenient to let us do the grunt work; this has the additional advantage that you don't need to worry about updating software, fighting bit rot, etc.
So -- send a mail to the operators of the GAVO data center at gavo @ ari . uni - heidelberg . de. Or call Markus Demleitner at ++49 6221 54 1837.
We would appreciate inclusion of the following sentence in the Acknowledgements section of papers which make significant use of any of our services and softwares:
'The <name of service or software> used in this paper was constructed as part of the activities of the German Astrophysical Virtual Observatory.'
Getting help from GAVO
If you need more information on GAVO, want to join the GAVO team or if you need help with GAVO/VO tools and services, please don't hesitate to contact us. Visit GAVO Team or Participating Institutes for contact details.