Cloudy is a spectral synthesis code designed to simulate conditions in interstellar matter under a broad range of conditions. It is provided for general use under an open-source License.
Please post questions or problems on the Cloudy user forum. Updates to Cloudy will be announced on that board.
C17.02, is released. This paper discusses what is new. Follow the StepByStep instructions for downloading and installing the code, or go straight to the DownloadLinks page to obtain it. NewC17 explains improvements and changes.
The next Cloudy workshop was scheduled for Athens, Greece, June 15-19, 2020 but was postponed due to the virus. For more details visit the workshop website and join the workshop user group at https://groups.io/g/CloudyAthens2020 to receive notices of developments.
Getting started with Cloudy
The Videos showing how to build and run Cloudy page has several useful videos.
StepByStep instructions for downloading and installing the release version, and running the code on various platforms.
Or you can go straight to the DownloadLinks page.
StellarAtmospheres in Cloudy are now very flexible. They are described on this web site rather than in Hazy.
KnownProblems are described on this page.
HotFixes are small corrections to the source that fix problems discovered after the current stable version was released.
The RevisionHistory pages list changes and new features in past, current and the next versions.
More information about Cloudy
A list of Cloudy papers and documentation can be found in this link.
Old versions of Cloudy are on the CloudyOld page.
The DownloadLinks page gives links to download the current version of the code, and trial versions if they exist.
Acknowledgments for help with Cloudy are on the AcknowledgmentsPage.
Outside pages related to Cloudy or related physics
ContributedMaterial - codes and spectra contributed by others.
Nick Abel used Cloudy to create a pair of animated gifs showing the time evolution of an H+ region with PDR after its ionizing star is turned on and then turned off. The first shows an advancing ionization front with the H+ layer moving from left to right into the atomic and molecular regions. The second shows the recombining cloud starting out ionized, becoming atomic, and eventually molecular.
A list of typos in AGN3 is posted here. (updated 2016 August)
A very old page giving miscellaneous information, including the following: people involved in its development, the code's history and style convention, computing at Cambridge in the 1970's, what the version numbers mean, the distinction between notation such as C+2 vs C III, how to call C from Fortran. Software contributed to drive Cloudy, other spectral synthesis codes, development software, atomic data, Kentucky, meetings on spectroscopy, and a collection of cloud images from across the internet.
The web page for the 1994 Lexington meeting on photoionization and shock models. This meeting was the first of a pair of meetings celebrating Mike Seaton's and Don Osterbrock's 70th birthdays. A book was published by Bob Williams and sometime later I posted the summary chapter describing our meeting.
These are donated scripts that help use Cloudy more efficiently. Do you have a useful script? If so please send a link to a page describing it to the Cloudy discussion board.
These developer's notes pages summarize our notes on developing Cloudy. You are most welcome to help.