CASDA Cutout Service

The Cutout Service allows astronomers to generate cutouts from curated survey datasets which are in the CSIRO ASKAP Data Archive (CASDA).

Currently available surveys are:

  • Rapid ASKAP Continuum Survey (RACS)
    • RACS-low DR1
    • RACS-mid Epoch 1
  • POSSUM
    • POSSUM Epoch 1

You can use this service to create cutouts around target objects from image data sets curated by survey science teams:

  • Enter cutout parameters
  • Either resolve an ‘Object name’ or enter the target coordinates. Decimal coordinates need to have at least one decimal place.
  • Multiple surveys may be selected.
  • When you click ‘Generate cutout’ the surveys’ images will be queried to find those overlapping the region of interest.

CASDA Cutout Service Results:

  • A tab is shown for each selected survey which has data for the region.
  • The list of potential cutouts are shown sorted in increasing distance of the centre of the source image from the target, but the results can be sorted.
  • Click the “download” icon to download the cutout in FITS format.

New Cutout:

  • Click “Options” and then “Refine cutout” from the cutout results page to change the existing cutout parameters.
  • Click on “Clear form” to clear all parameters after you have returned to the cutout page.

Cutouts from specific image cubes

  • CASDA is also able to produce cutouts from specific image cubes of interest.
    You can use the ASKAP Observation Search to find the right image cube and then use the “cutout” icon to request a cutout.

Cutout Service – parameter selection

Screenshot of Parameter Selection

Select parameters to generate a cutout:

Object name

Enter the name of an object and click ‘Resolve’ to automatically populate the Right ascension/Declination fields. This queries VizieR for the object name.

Right ascension/Declination

Enter the coordinates of the centre of the desired cutout manually, if not you did not enter an Object name.

Survey

Select the survey(s) you want.

Cutout Radius (arcmin)

Enter the radius of the desired cutout.

Generate Cutout

Click the button to generate the cutout.

When you click “Generate cutout” the surveys’ images will be queried to find those overlapping the region of interest.

CASDA Cutout Service – results

Screenshot of CASDA Cutout Service Results

Survey tabs

A tab is shown for each selected survey which has data for the defined region.

The list of potential cutouts are shown sorted in increasing distance from the target, but the results can be sorted using up and down arrow buttons.

The following columns are displayed:

  • Title: Describe cutout
  • Size: Size of the cutout
  • Distance from image centre (deg) Distance from image centre
  • RA(J2000): Right ascension (J2000)
  • Dec (J2000): Declination (J2000)
  • Preview: Preview of the cutout

Click the download button to download the cutout in FITS format.

Other features:

Show 15 entries

By default 15 results are displayed per page. This can be changed to 5, 10, 15, 25, 50 or 100 per page.

Refine Cutout

Click the button to return to the CASDA Cutout Service page where the selected parameters have been retained.

Showing x to y or z results

Pagination information about the number of results.

Paging

Options to move between pages.