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CASDA User Guide

The complete CASDA User Guide can be found at and covers alternate access methods such as Virtual Observatory tools and scripted/automated access.

CASDA Observation Search Results

When you perform a CASDA search, the results will appear in a table view similar to the screen shown below:

The page heading indicates whether you are viewing released or unreleased data products, depending on your selection on the search page.

Note that the results are separated into multiple tabs. Each tab contains search results of particular data product types, as indicated by the tab heading. The number of search results returned under that tab is also displayed.

The following tabs may be available:

  • Catalogues: Lists catalogues matching your search criteria.
  • Image Cubes: Lists image cubes matching your search criteria.
  • Spectra: Lists image based data products matching your search criteria, such as spectra and moment maps.
  • Visibilities: Lists visibility files (Measurement Sets) matching your search criteria.

If there were no results for a given data product, the relevant tab will not be displayed. If there were no results matching your search criteria at all, then no tabs will be shown - instead a message will indicate that no results were found.

Page Elements & Features

Refine Results

If there are options to further filter your results without returning to the search page, these options will appear in this section. The "Clear all filters" link will reset the filters.

Refine Search

Use the 'Refine Search' button to return to the CASDA Observation Search page, where you are able to amend your search criteria, and perform the search again. This function retains the search values that you previously entered.

Sorting Results

You can sort the results by ascending order by selecting a column heading at the top of the results table. The column headings will differ depending on the tab you are viewing. Select it again to sort in descending order.

Results Per Page

Use the "results per page" links to alter the number of results shown per page.

Navigate Pages

Use the page controls (after the results table) to navigate through multiple pages of results.

Retrieve Selected Data

To retrieve data:

  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" link.

See the CASDA section on the Access or Download Data help page for more information.

Note: To access image files or visibilities, you must be logged into DAP. You can register an OPAL account in order to get authenticated access to the DAP. (See also: the CASDA section of Access or Download Data)

Catalogue Formats

On the "Catalogues" tab, there will be a dropdown box allowing you to select a format when accessing / downloading catalogue data.

Use these options to determine the file format, and the level of aggregation.

File formats include:

  • CSV - Deliver the file(s) in "CSV" format, which can be opened in applications such as MS Excel.
  • VO Table - Deliver the file(s) in "VO Table" format, which can be used with VO clients such as Topcat.

Aggregation levels include:

  • Individual - A file will be prepared for each selected catalogue
  • Grouped - All catalogues of the same Catalogue Type will be grouped into a single file. That is, you will receive a file for each catalogue type.

For example, if you selected the following files for download:

Then chose to receive those files in the format "CSV - Grouped", you will receive 3 CSV files:

  • One for Continuum Islands containing 1578 entries;
  • One for Continuum Components containing 2708 entries; and
  • One for Polarisation Components containing 2 entries.

Alternatively, if you chose to receive files in the format "VO Table - Individual", you would receive 5 VO Table files, one for each selected catalogue.

Fields to Note

Please note the following fields found in the results listings. Some of these fields may not appear on all results tabs if they are not relevant to the data product types being displayed.

Selection box

Select these boxes to identify which items in the results you want to access or interact with.

Items which you cannot access (such as unreleased data products) will display a lock icon instead of a selection box.

You can select & deselect all checkboxes in a results tab by selecting / deselecting the checkbox in the results table column heading.

Scheduling Block ID

This is the Scheduling Block from which the data product was produced.
File Size

This is the size of the data product. There are limits to the volume of data can be accessed at one time.

This is the project that the data product belongs to. You can view the project title by hovering over the project code.

By clicking the link, you can view the project's Collection which contains that data product. The collection holds additional metadata about that project, such as the Principal Investigator, a list of Contributors and a description of the project.

A project may have more than one collection, typically two - one collection for catalogues and another for images, cubes & visibilities. The project link will take you to the relevant collection.

Num Entries

This column appears alongside catalogues to indicate how many records are present in the catalogue.
Data Quality

This field indicates the level of quality of a data product, as assessed by the project team. Poor quality data is still archived and made available, as it may be useful in certain contexts. The following are the possible quality states:

  • Good
  • Uncertain
  • Bad

The following additional states are also possible when viewing unreleased data:

  • Not validated - A quality level has not yet been determined
  • Unreleased - A quality level has been determined, but the data product has not been publicly released
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