Author: Markus Demleitner
Date: 2021-05-28

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.


DaCHS' documentation is now maintained on github; formatted versions are available on readthedocs . Please file documentation bugs there; other contributions are always welcome.

Reading guide

You do not need to read all of the documentation to get started.

Of the installation guide, you probably only need the first couple of pages. At least skim over the tutorial before starting out, though, so you know what's discussed in there to return when you have a particular sort of data at hand.

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.

Always keep the reference under your pillow. Even the authors regularly go back there.

Almost all RDs for the services at the GAVO data center are available for your inspection, and the element reference may help you locate those relevant to whatever you're trying to do. 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.

Deployment Options

For Data Center Operators

Special Topics for Operators

For VO Data Providers

Library Documentation

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 (develNotes.html, develNotes.pdf, develNotes.rstx)


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 has happened once in the past ten years).

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.

Material related to DaCHS and the VO in general is also published now and then on GAVO's blog

More interactive support may also be available via IRC, channel #gavo on You can also try mumble via


If you want or need to reference DaCHS, I suppose you should be citing 2014A&C.....7...27D. If you can't bring yourself to boosting an Elsevier journal's impact factor, you have my sympathies, and you're welcome to cite the (less informative, more difficult for bibstyles) ASCL entry at 2018ascl.soft04005D.