Use Case:  List observed sources.

Goal: Return a catalogue indicating what projects have observed sources with some set of specific observational parameters.

Contact Author:   G.Fuller

Priority: Critical/Major

Frequency:  Daily ?

Preconditions: 

1. Archive is running
2. User authenticated and connection to archive established

1. Request submitted which specifies the observational parameters of interest. For example: frequency or frequency range, range of baselines, source name or coordinates (and allowable uncertainty), type of observation including whether source was calibrator or science target, observing conditions, date/time range
   
2. If source name supplied, but not coordinates, resolve the name to coordinates using either an internal archive resolver or external web service are requested in request.
   Exception Course: Return error indicating source name not resolvable to meaningful position
3. Validate requested parameters are within acceptable ranges.
   Exception Course: Return error indicating which parameters are out of range.
4. Search for observations matching criteria. For each observation found check whether user has permission to access data.

Postconditions:

1. A catalogue of observations matching the requirements is returned. This catalogue should include sufficient information that the data corresponding to these observations can be retrieved without further searching. Just returning the project ID is not sufficient.
   

Issues to be Determined or Resolved:  

1. Access permissions: Need definition and what they allow a user to do. For example, are there permissions which allow a user to know that a certain set of data exists but not access it, or can the user not even determine whether the data exists. If the latter, is the user told that their could be data which they are being prevented from searching ?

Other Notes: