Author: Markus Demleitner
Date: 2024-04-29

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.


The upstream (non-spying, no-ads) documentation for DaCHS is on If you prefer a sphinx theme, there is also a readthedocs copy .

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

Material related to DaCHS and the VO in general is also published now and then on GAVO's blog; there's an RSS feed for that, too.

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


Mailing lists

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 fifteen years).

There is also the DaCHS-support list, which is a relatively low-volume list for discussions of the type “how do I?“ or even informal bug reports. It has a public archive, and other users can profit from our (and your peers') answers. If you want to read of other DaCHS' users ideas and woes, please subscribe that, too [Nov 2023: the list is slightly broken, so if there's no response to something you posted there, please alert us via mail to].

Bugs, Distress Signals, and the Like

DaCHS has a bug tracker on, which you're welcome to use. Sorry, you cannot log in on that site yet; we're working on it. If you need to do anything that requires authentication at this point, please drop us a mail.

You can also send mail to Unless you tell us not to, we may put bug reports sent in that way on the gitlab bug tracker.

More interactive support may also be available via IRC, channel #gavo on, and you can try mumble via But these are synchronous, so nobody will there if all of us are busy elsewhere.


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.