CASA Data Repository

Each CASA distribution comes with a minimal repository of binary data that is required for CASA to function properly. This repository includes Measures Tables that deal with the Earth Orientation Parameters (EOPs), reference frames, as well as ephemeris data. In particular the EOPs include predictions for the near future which drift until they are well determined. They are regularly updated in the CASA data repository at NRAO of which the user's CASA installation contains a snapshot. Because of this, the distribution data repository must be updated occasionally. Other data that is updated less frequently is also stored in the repository, such as beam models, antenna and Jy/K correction tables, and the antenna configuration files for the CASA simulator.

A snapshot of this repository is included in each tarball distribution of CASA, and in the casadata module for CASA 6+. The owner (in the Linux filesystem sense) of the CASA distribution can update the data repository to the latest available version by running from within CASA:

CASA <2>: ! update-data

or (CASA 6 only) from the shell prompt outside CASA:

bash$ cd 
bash$ bin/pip3 install --upgrade  --extra-index-url https://go.nrao.edu/pypi casadata

or, when using the modular pip-wheel CASA distribution:

bash$ pip3 install --upgrade  --extra-index-url https://go.nrao.edu/pypi casadata

Note that for CASA 6, these methods will update to the latest version of the casadata module which is only updated ca. weekly.

It is also possible to use rsync to perform the update accessing the NRAO repository directly rather than the latest casadata module.

For CASA 5 use

bash$ cd /data
bash$ rsync -avz rsync://casa-rsync.nrao.edu/casa-data .

For CASA 6 use

bash$ cd 
bash$ cd `find lib -name __data__`
bash$ rsync -avz rsync://casa-rsync.nrao.edu/casa-data .

Generally, the above rsync command can be directed at any destination and so the command can be used to get a copy of the partial data repository as used in the CASA distributions (CASA 5 and 6). This does not contain the regression data.

It is also possible to use rsync to get the complete data repository:

rsync -avz rsync://casa-rsync.nrao.edu/casa-data-repository casa-data

In this case you get the entire repository, but there is no way to pick and choose which pieces you get.

Recommended update intervals

One of the above data repository update methods should be used regularly for all CASA installations which are currently in use for processing recent data. Legacy installations processing old data do not have to be updated because the relevant contents of the Measures Tables is not changing anymore for the more distant past.

For observatory use, the update period should not be longer than weekly in order to have the EOPs up-to-date for upcoming observations. The shortest reasonable update interval is daily and the recommended method is via rsync.

For offline data analysis use, the update period should not be longer than monthly. Weekly update is recommended.

Typically, the administrator of a CASA installation sets up a cron job to perform the update automatically.