external database files.

The code has a broad user community. As described below, we ask that users reference paper if the code is used in a publication. At the time of this writing there are nearly 200 citations to F98 or the code’s documentation each year. We maintain a [discussion board](http://tech.groups.yahoo.com/group/cloudy_simulations)[^5] where users can ask questions and where we post announcements of updates to the code.

### Material available on [[](http://www.nublado.org)]{}

[[](http://www.nublado.org)]{}, the code’s web site, gives complete access to files and information about . The site, built using [trac](http://trac.edgewall.org/), gives top level links to a variety of items. These include:

-   [Step by step instructions](http://www.nublado.org/wiki/StepByStep) for downloading, building, and running the code. We provide links to a large tarball for the download, and makefiles are used to build the code.

-   [Stellar atmospheres](http://www.nublado.org/wiki/StellarAtmospheres). As discussed in Section \[sec:StellarAtmospheres\] below, it is possible to use grids of stellar atmospheres in deriving the incident radiation field. This page gives more details and links to available grids.

-   [Known problems](http://www.nublado.org/wiki/KnownProblems), and [hot fixes](http://www.nublado.org/wiki/HotFixes). No code is perfect. Users should post questions or bug reports on the [discussion board](http://tech.groups.yahoo.com/group/cloudy_simulations). We provide a list of known problems. These are deficiencies which we know about, 