Nov 4, 2019: CASA 5.6.2 is now available for general use and pipeline processing of VLA data. The CASA 5.6.2 version has been scientifically validated for manual processing and VLA pipeline processing. ALMA users are recommended to use CASA 5.6.1. Details can be found in the CASA Docs 5.6 Release Notes.

Oct 1, 2019: CASA 5.6.1 is now available for general use and pipeline processing of ALMA data. The CASA 5.6.1 version has been scientifically validated for manual processing of data from ALMA and VLA, and also for use of the ALMA Cycle-7 pipeline. Details can be found in the CASA Docs 5.6 Release Notes.

June 11, 2018: CASA Docs, the official CASA documentation, now includes all tasks descriptions plus general pages on data reduction in CASA.

Obtaining the CASA Release

Supported Operating Systems

The latest CASA release 5.6.1 is available for the following operating systems:

  • Linux
    • Red Hat 7
    • Red Hat 6
  • Mac OS X
    • macOS 10.14 (Mojave)
    • macOS 10.13 (High Sierra)
CASA may also work on other flavors of Linux, but only the operating systems listed above are officially supported by CASA, because these we run regular tests on.

OS X users should be aware that it may be necessary to temporarily bypass Apple's Gatekeeper security system to run CASA for the first time after downloading it. This can be done by using "Ctrl+click" on the downloaded application file and selecting "Open" from the contextual menu. Details can be found here.


Please follow these links for downloading the current release of the code for your specific operating system. Installation instructions are provided, too. Links to previous releases are given at the bottom of this page.
CASA Pre-releases are code under development. Use with caution as the code is still undergoing changes, is less tested and not well documented.

Alert for pipeline use: The ALMA and VLA pipelines are included only in certain versions of CASA. Please ensure to download the correct CASA pipeline version for your data. The latest versions of CASA with a pipeline that has been scientifically validated for ALMA or VLA are given below.

CASA Pipelines
CASA Release
CASA Pre-releases
CASA containing ALMA pipeline
CASA containing VLA pipeline
Linux Packages Installation
Red Hat 7
Red Hat 6
Mac OS X Packages Installation
OS X 10.14 (Mojave)
OS X 10.13 (High Sierra)
* The CASA 5.6.2-2 version for general use is identical to the CASA 5.6.2-2 pipeline version that is used by the VLA pipeline. Both links therefore point to the same casa-pipeline-release-5.6.2-2.x file, which has the VLA pipeline included.
** Pipeline version number 42866


CASA now collects usage statistics including task execution timings and crash reports. This data will be periodically sent back to NRAO to guide future priorities and decision making. All collection is anonymous and contains no scientific or personal data.

You can disable telemetry by adding the following line in your ~/.casarc file: EnableTelemetry: False
For more information, see CASA Docs

Release Information

The Release Notes and Known Issues of the 5.6 releases, as well as previous releases, are available in CASAdocs

Hardware Requirements

The reduction of radio data in CASA can be demanding in terms of hardware, and a balanced configuration regarding memory, processing power and file I/O may be required to efficiently run CASA.

Recommendations on the CASA hardware requirements for VLA and ALMA data can be found on the 'Hardware Requirements' pages of CASA Docs.

Open-file errors: For mosaic imaging in tclean, it may be necessary to raise the ulimit to avoid and error “too many open files”, e.g. by setting ulimit -n 16384. In some cases, it is not sufficient to only raise the soft limit, but also the hard-limit, which requires admin/root permissions. ALMA strongly recommends users to set ulimit to at least 16384 for both the soft and hard limit to avoid potential open-file errors with mosaic imaging in tclean.

Older Releases

CASA 5.6.1 (Redhat 7 - Redhat 6 - MacOS 10.14 - MacOS 10.13)

RedHat 7 (CASA 4.7-5.6.0)
RedHat 6 (CASA 4.3-5.6.0)
RedHat 5 (CASA 4.3 - 4.6)
RedHat (CASA <=4.2.2)

MacOS 10.14 (CASA 5.5-5.6.0)
MacOS 10.13 (CASA 5.3-5.6.0)
MacOS 10.12 (CASA 5.0-5.4.2)
MacOS 10.11 (CASA 4.6-5.1.2)
MacOS 10.10 (CASA 4.4 - 4.7)
MacOS 10.9 (CASA 4.4 - 4.5)
MacOS 10.8 (4.3); OSX 10.8 (<=4.2.2)
MacOS 10.7
MacOS 10.6
MacOS 10.5

Other Links

CASA Source Code -- (Notes).

Contributed CASA scripts

If you need additional help, please consult our NRAO helpdesk or ALMA helpdesk

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