Obtaining HST data from CADC
The CADC started the Hubble Space Telescope Project in March 1986. The
center became operational in middle 1987 using standard calogue data
only because launch delay of the Hubble telescope.
Very soon, in order to distinguish themselves from the main STScI center, the CADC started implementing
important added-value features to complement what was already available.
In principle, the files delivered by CADC are exactly the same as the
ones delivered by STScI
and ST-ECF. But sometimes, the processing software versions are
different. Updates are
installed more frequently at CADC and ECF and usually later at STScI
because of operational constraints. But for 99.9%
of the cases, we are all running the same basic infrastructure. When
differences are detected, it is often due to cosmetics
considerations and are not affecting the pixels array.
The CADC is also responsible of producing the previews which are in used in all three
HST centers. This way, the CADC is insuring that its pipeline software is running
correctly when the observation become public, usually one year after the acquisition date.
The CADC has no rights to distribute nor manipulate non public data.
Observations searches Using web interface
The HST web based search interface provides a means to search the HST
archive. Currently, the page limits the number of rows to be returned. The
default is 100 rows, but the limit can be increased to a maximum of 1500
rows. This limit is imposed due to the length of time needed to render
the search results in HTML. Even 1500 rows will take some time to render
in HTML. However, if you wish to make a number of searches and requests,
the web interface should serve you well. You may wish to perform the
same basic search, but limit the results by including a filter and/or
observation time limit.
Once your selection have been specified and you are getting your search results in an html table, you could then select the datasets you want to get from CADC by
marking them (checking the "Mark" box on the left most column. Then just hist the download data button .
Observations searches VO Services
All public HST images are now available in the VO registeries as CADC service. Please use any VO registry compatible tool such as Aladin
to browse and get HST data from CADC.
ALADIN = http://aladin.u-strasbg.fr/
In addition, one could use the CADC's new OCTET application which main feature is its ability to search the entire sky for common observations in selected
Octet = http://www.cadc.hia.nrc.gc.ca/cvo/
Data retrieval using web style services
The CADC is also providing a convenient programmatic interface to its entire HST datasets collection. Please consult the on-line manual
for more information:
This interface allows you to access directly the HST dataset of your choice. For this though, you will have to know the filenames
associated to each datasets. Please consult the CADC's documention page for HST filenames for each instrument and project.
For the HLA archive, just replace the HSTCA archive by HLA
In short the interface could be use the following way: