Author:Markus Demleitner

The GAVO Data Center Helper Suite (DaCHS) is a publishing infrastructure for the Virtual Observatory, including a flexible component for ingesting and mapping data, integrated metadata handling with a publishing registry, and support for many VO protocols and standards.


All of this is very much work in progress. Users asking for elaboration are certainly good indicators of where need is greatest.

What to read when?

Obviously, you should start with the installation instructions (have a brief glance at them even if you install from Debian package). You should then probably read and work through the tutorial to get a feel for how DaCHS works. Once you have data and want to go live, you’ll have to read the operator’s guide. That’s about all there is to read sequentially.

When you get error messages you don’t understand, check the “Hints on common problems”. When you have some funky litte requirement the solution for which is not immediately obvious, try the “How do I” document. If what you want is not covered, ask the authors.

The reference is, well, the reference, and I’m afraid you’ll have to look up things in there fairly regularly. The good news is that there’s examples in the index to elements and attributes in the GAVO DC; these are essentially live, and as long as you’ve had a look at the reference, there’s nothing wrong with lavishly copying from there.

You can ignore the topic guides (booster grammars, preprocessing, anything else that might yet come) until you notice you need to read them.

DaCHS developer Documentation

  • Epydoc-generated API documentation. Note, however, that none of this is, as yet, guaranteed stable API. Very little will be. The main purpose of this is to help understanding the code as it is; but of course you should tell us “I need this function in a stable API” when you do, and we promise to regard such requests with favor.
  • Development notes


To obtain the software (or parts of it), see


If you run a DaCHS server, please subscribe to the DaCHS-users mailing list. It is low volume (less than one mail a month), and you get to know when new releases come out. We’d also appreciate being able to alert our users in case a security hole should be discovered in the software (which hasn’t happened so far, FWIW).

If you have questions regarding DaCHS, we’d appreciate if you subscribed and sent your question to the DaCHS-support list (if all support requests went on the list, we’d expect a volume of about one mail per day, but let’s see). It has a public archive, and other users can profit from our (and your peers’) answers, which is why we prefer the list to questions sent directly to; these will of course still be answered.