Astronomers can search the WSRT archive  online (temporarily unavailable, please use SDC-Helpdesk) for WSRT data that have been taken since mid-2000.  Data that are in the public domain can be requested by creating a ticket through the SDC-Helpdesk identifying the corresponding project name(s) and the sequence numbers of the requested data sets.

The WSRT archive can be searched using this tool. (temporarily unavailable, please use SDC-Helpdesk)

Retrieving data from the WSRT archive

Archive data can be provided upon request opeining a ticket via the SDC-Helpdesk. The email should contain the related project reference code and the sequence numbers of the requested data sets, as well as a specification of the requested data format (MeasurementSet or FITS). The necessary information is available from the WSRT ArchiveBrowser (see description below).

The WSRT science support will check the availability of the data: archive data are generally public one year after the last observation of a project has been made, but exceptions may be active. If the data are in the public domain, they will be uploaded on the ASTRON ftp server and the archive user will be notified on how to download them. For observations that are not older than slightly more than a year, it is not very likely that the corresponding data sets are publicly available already.

No guarantee is given of the completeness and reliability of the received data.

Reported issues:

Data until 6 December 2002 (solved): Wrong epoch in the data headers and tables. The issue is solved and should not turn up again. However, the astrometrical accurary of data taken until 6 December 2002 should be checked against a reference catalogue (e.g. NVSS).

Usage of the archive browser

The WSRT ArchiveBrowser can be used to search the WSRT archive and to obtain the information necessary for a request. A detailed description can be found here or by clicking on the "?" buttons on the ArchiveBrowser form.

In a first step, the archive user will search the archive for appropriate observations of their sources, mostly making use of the possibility to specify a position and a search area in the ArchiveBrowser form or by providing a list as an ASCII file (batch mode). If the search is successful, the ArchiveBrowser returns a list of observations together with a description of the measurements in a separate window of the browser.

For an archive request, the user requires the project code(s) and the sequence number(s) of the measurements. The sequence number of a single measurement is listed on the top right of each entry (Seqnr. : XXXXXXXX) in the list returned by the ArchiveBrowser. The project code is a combination of two identifiers, the semester, and the project number, separated by a slash character ("/"). It is always identical to the first two character sequences separated by a slash character ("/") in the "ObjectName" code listed for every observation in the return list of the ArchiveBrowser: "ObjectName : XXXX/YYY/Object" corresponds to the project code XXXX/YYY.

After a list of sequence numbers of appropriate target observations has been identified, the archive user will probably also need to locate calibrator measurements accompanying the target observations. This can be achieved by resetting the  ArchiveBrowser form (click on button "reset form" at the bottom of the form) to then enter the project code(s) under "Project ID" (format: XXXX/YYY, without leading or trailing whitespaces, with XXXX/YYY derived from the ObjectName as described above). The ArchiveBrowser will then return a list of all measurements in the specified project including calibrator measurements. In most (but not all) cases, it is standard to observe two primary calibrators per target observation with the WSRT, one immediately before the target observation, one immediately after the target observation. Hence, the sequence numbers of calibrator observations belonging to a certain target should not differ by a large number from the sequence number of the target observation. In doubt, the more detailed description (including observing times) of the observation(s), which can be accessed by clicking on the "more >>" button in the list returned by the ArchiveBrowser should clearly identify the appropriate calibrator measurements (and their sequence numbers).

In summary, an archive search consists of the following steps:

1. Use the  WSRT ArchiveBrowser to check if appropriate target observations are present in the archive
2. Identify the sequence numbers and the project codes of the target observations (first two character sequences of the "ObjectName")
3. Enter the project codes in the WSRT ArchiveBrowser "Project ID" field to identify appropriate calibrator measurements and their sequence numbers

Archive request

Two types of requests directed to the SDC-Helpdesk can be answered in a relatively short time:

1. A request to check the availability of archive data. The requesting user provides project codes and sequence numbers. A request like example 1 below can be answered in a short time, but not a request like example 2.
2. A request for checking the availability of data and for making them available to the user. The requesting user provides project codes, sequence numbers, and requested data format (FITS or MS). A request like example 3 below can be answered in a short time, but not a request like example 4.

A properly configured request of type 2 will be answered by sending the requesting astronomer a download link to download the archive data, or, if proprietory material has been requested, a notification that the data cannot be made available.