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CASDA User Guide

The complete CASDA User Guide can be found at http://www.atnf.csiro.au/observers/data/casdaguide.html and covers alternate access methods such as Virtual Observatory tools and scripted/automated access.

Overview

Survey data products which have not been validated or publicly released can only be accessed by project team members in the DAP. Once validated and released all survey metadata will be accessible. Unauthenticated users can only access catalogue data although they will be able to view a list of all data product types. Logged in members will also have access to non-catalogue data (images, cubes, visibilities etc.).

Users can freely register an OPAL account to get authenticated access to data.

Please keep in mind that CASDA contains some very large files. The linked table provides best-case estimates of download times based on the size of the files.

Access options include download via the web, or access within the Pawsey Supercomputing (PSC) facility.  Please note: if you plan to access data within PSC, you will need to separately apply for and arrange use of the high performance compute facility.

There is a limit to how much data you can download at one time. Some browsers may also limit the size of downloads to around 2GB.

Accessing CASDA Files

CASDA data can be accessed by conducting a CASDA Observation Search and selecting files from the search results page (see: Domain Search), or by finding the DAP Collections containing the data and navigating to the collection's Data tab. You can find a collection by either conducting a DAP Search (see: Search Data) or opening a Project code link from the CASDA Observation Search Results page.

In either case, you can access CASDA data through the following steps:

  1. Select the data you wish to access by marking the checkboxes next to the items you're interested in
  2. Some data types may allow you to choose a format (see below)
  3. Choose your preferred retrieval method from the "Retrieve via:" dropdown
  4. Select the "retrieve selected data" button / link.

A screen will then be displayed showing the status of your Data Access Request (see below) and will provide details for accessing your data once it is ready.

Selecting the checkbox in the column heading will toggle selection of all files on all pages within the search results.

You may need to tell your browser to allow pop ups from the DAP to see this page display.

Data Access Request Status

Some CASDA data will take a long time to prepare. The Data Access Request Status page will show you the progress of your request. It will update every 30 seconds or so.

You can copy or bookmark the URL and return to the page at a later time.


Once your data is ready, the page will provide the relevant details and links to download each file. A checksum file will also be made available for each requested data product.

You can download:

  • download files individually by selecting a link
  • download a text file containing all the links to files by clicking the 'Save links as text file' hyperlink
  • download all files in a TAR file by clicking the 'download tar' hyperlink



Data access jobs will expire after a set time to allow space to be cleared for other users. The status page will provide your job's expiry details.

CASDA Checksums

CASDA provides checksums for catalogue data, images and visibilities. The checksums can be used to ensure that the data files were downloaded correctly.

Please download and use the attached scripts to calculate checksums and verify checksums.

 

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