GAVO DC Virtual Observatory Libraries

Some parts of DaCHS useful for other VO software are available as separately installable libraries.

Common Installation Instructions

The most convenient way to install the software provided here is by using the APT repository on Debian-derived distributions. Failing that, you can install them by grabbing tarballs as given below and using setuptools.


This is yet another library to parse and generate VOTables in python, with the primary claim to fame that it lets you stream data. There's also a TAP client included on the idea that TAP is going to be something everyone dealing with VOTables is interested in.

You can obtain a source tarball or get the python3-gavovotable package from our APT repositoy.


A python library that processes a significant part of IVOA Space-Time Coordinate specifications. This includes parsing and generating STC-S and (parts of) STC-X as well as system and unit transformations.

For details, refer to the STC library documentation. Although in productive use in GAVO's data center, the library as a whole certainly is alpha so far, and it is unlikely it will go further, because the underlying standard is on the way out.

The library is available as a source tarball (using ez_setup) or as package python3-gavostc from our debian repository.


A python library that parses ADQL, infers units, types, etc, morphs it into postgres plus q3c, etc.

We do not provide packages for this yet, but you could check out the SVN. If you are interested in adopting this in your own code (you'd be most welcome to; please don't start another ADQL-to-SQL translator in python, as there are already too many of those), let us know and we'll certainly accomodate you.


This is a collection of various utility-type modules that serve as a common dependency. It probably is of little interest in itself. You will need it for any of the GAVO modules, though setuptools and of course APT should make sure it is automatically installed.

If the automagic fails, you can sill download the source tarball manually. In the APT repository, the package is called python3-gavoutils.

Other libraries

DaCHS contains code for, among other things, handling Vizier-like expressions, units, VOTable parsing and generation, etc. If you are interested, let us know and we'll see whether we can provide sufficiently isolated libraries for these purposes.

Installation Problems

If your installation fails with an error like zipimport.ZipImportError: bad local file header in <something>, simply try again. This appears to be a subtle bug in ez_setup.