Using the HLA with Aladin

This document shows how to use the HLA footprint service to overlay the footprints from HST archival data on a DSS (or other) image. For a demonstration using a specific example, see the training movie.

You first need to select the object you wish to investigate. Select one of the following in the APT Tree Editor:

  • a Target
  • an Observation (Phase I)
  • an Exposure (Phase II)

    Bring up the View in Aladin tool, and load a DSS image.



    To access the HLA footprint server, go to the Aladin File menu and select Open, which brings up the Aladin Server Selector. On the left side (where the Image Servers are), select the Archives/HLA. Note that since we have selected a Target, Observation, or Exposure in the APT Tree Editor, the coordinates for the HLA search are already in place. You can modify the search radius if desired. Select the appropriate Instrument, and hit Submit. You can also select the level, but in most cases, the Best Available is appropriate



    You now have a listing of all the ACS observations in your search area. The results come up sorted by spectral element, with the filters collapsed.



    You can change the sorting by clicking in an open area in the server window and selecting SORT. This brings up a popup from which you can select which parameters you wish to sort by.



    You can open the search parameters to see the results.



    Note that the images available through Aladin are the PREVIEW images.

    To see where the various filters appear on the DSS image, run your cursor over the filter in the Server Selector window, and the area where the data exists will be highlighted on the DSS image



    If you want to save the footprint or retrieve the image, then select the dataset you want in the Data Info Frame. Selecting FoV in stack will put the footprint in your Aladin stack. Selecting Load will put the preview image into Aladin. If you want to access the full FITS image, then copy the URL in the Data Info frame to your browser.


    Note that the data available here are the individual datasets. In the HLA, you also have access to the enhanced data products, such as the combined (e.g. multi-drizzle) data, and source catalogs.


    Last modified: February 7, 2014.