Functional requirements

The end-user shall access the archive via the internet and Graphical User Interfaces. Pixel data shall be supplied with astrometric WCS, flux calibrated pixels, and confidence maps which include bad pixel flags/masks; object catalogues shall be merged across avaliable passbands and shall include error estimates for subsets of the more important parameters.

The end-user shall be offered:

• pixel data in any available passband over small areas of order up to a few tens of arcmin (TBD) with associated matched object catalogue
• larger areas from survey data, mosaiced on-the-fly and blocked down as required/appropriate
• optimally stacked images where survey data are available
• seamless, merged multi-colour, multi-parameter catalogues with best available astrometric and photometric calibration from survey data
• ability to specify the object parameters in the user-extracted subset from survey data
• survey database federation with other source catalogues (primarily SDSS and Schmidt photographic sky surveys)
• ability to construct readily meaningful optical/IR colours for all sources, not just point sources, in the overlap with the SDSS
• ability to carry out efficient queries to locate objects conditional on ranges of the following parameters: spherical co-ordinates in equatorial/Galactic systems; radius within given sky position; JHK magnitudes and any linear combination thereof; object size; object classification (stellar/non-stellar/other) ¹

• ability to carry out queries on any other stored parameter
• for all queries, archive shall be able to return an estimate of the number of objects to be located and time required to implement the search (not only for user information, but also to help archive management, scheduling of queries, etc.)
• ability to carry out queries on recalibrated quantities or previous versions of calibrations
• ability to perform repeated queries (`batch' mode) on survey data
• ability to create simple finder chart (for use while observing for example)
• ability to access `best', or all of a set of duplicate measurements where they exist in overlapping survey data (eg. generate light curves and/or proper motions from duplicate measurements of the same object)
• general access to housekeeping data - eg. what's currently available; how good is it; in short, user access to all housekeeping data specified in the previous section