CASDA Python API

Provides a simple Python API to access images hosted on the CSIRO ASKAP Science Data Archive (CASDA).

Installation

casdapy has the following dependencies which will be downloaded automatically if installed with pip.

• python>=3.8
• astropy
• astroquery
• click
• PyPika

Download this repository and install with pip, e.g.

git clone https://github.com/askap-vast/casdapy.git
pip install ./casdapy

or install directly from GitHub, e.g.

pip install git+https://github.com/askap-vast/casdapy.git

The casdapy CLI

casdapy is primarily intended to be used as a library, but a CLI is included for common tasks. You may find this CLI does what you need.

An executable script named casdapy is installed with the package. Run it with --help to see usage details.

$ casdapy --help
Usage: casdapy [OPTIONS] COMMAND [ARGS]...

Options:
  --verbose  Show more logging information. Useful for debugging. Defaults to
             False.

  --help     Show this message and exit.

Commands:
  download  Query CASDA and download results.
  retry     Download files from an existing CASDA job.
  verify    Verify CASDA download checksums.

Note that --verbose is an option for the parent casdapy command. To turn on verbose logging, pass it as an option to casdapy, not the subcommand.

Subcommands

download

Search for images and catalogues on CASDA that match various search criteria (e.g. image polarisation, SBID number, cone search) and downloads the results. Will split the data download into several CASDA jobs for large result sets. Run casdapy download --help for more details.

retry

Retry downloading the data files from an existing CASDA job. Run casdapy retry --help for more details.

verify

Verify data files downloaded from CASDA by calculating their checksums and comparing them to the .checksum files provided by CASDA. Run casdapy verify --help for more details.

Examples

Download the component catalogue, island catalogue, restored Stokes I image, and the Stokes I noise image for ASKAP SBID 11427.

casdapy --verbose download --sbid 11427 --image-type cont.restored.t0 --image-type cont.noise.t0 --image-pol I \
--catalogue-type catalogue.continuum.component --catalogue-type catalogue.continuum.island

Use as a library

You can use casdapy in your own scripts to perform CASDA queries and download results. There are a number of functions defined in casdapy.casdapy. Refer to the function docstrings. Note that this package follows PEP8 naming conventions where interfaces that are not intended to be public (and therefore are not guaranteed to remain stable) are named with a leading underscore, _.

Feedback

Feedback is very welcome! Please report any issues or suggestions using the GitHub issue tracker.