The SuperCOSMOS Science Archive

The SuperCOSMOS Sky Survey ( SSS; Hambly et al., 2001) consists of digitised scans of Schmidt photographic survey material in a multi–colour (BRI), multi–epoch, uniformly calibrated product. It covers the whole southern hemisphere, with an extension into the north currently underway. Public online access to the 2 Tbytes of SSS pixel data and object catalogues has been available for some time; data are being downloaded at a rate of several gigabytes per week, and many new science results are emerging from community use of the data. In this poster we describe the terabyte–scale SuperCOSMOS Science Archive2 (SSA), which is a recasting of the SSS object catalogue system from flat files into an RDBMS, with an enhanced user interface. We describe some aspects of the hardware and schema design of the SSA, which aims to produce a high performance, VO–compatible database, suitable for data mining by ‘power users’, while maintaining the ease of use praised in the old SSS system. Initially, the SSA will allow access through web forms and a flexible SQL interface. It acts as the prototype for the next generation survey archives to be hosted by the University of Edinburgh’s Wide Field Astronomy Unit, such as the WFCAM Science Archive of infrared sky survey data, as well as being a scalability testbed for use by AstroGrid, the UK’s Virtual Observatory project. As a result of these roles, it will display subsequently an expanding functionality, as web – and later, Grid – services are deployed on it. 1. Relational Model for the SSA Data The photographic material used in the SSA comprise the SERC J/EJ, ER/AAO– R and I original surveys along with first epoch R data from the ESO–R and POSS–I E copies in the southern hemisphere; ultimately, the northern hemisphere will be included via POSS–II J, R and I copies with POSS–I E copies again providing early epoch R data. Hence, 8 single colour surveys on 3 different field systems (ESO/SRC, POSS–I and POSS–II) make up the source material. The rest of the schema follows from the several individual colour/epoch plates in http://www-wfau.roe.ac.uk/sss http://thoth.roe.ac.uk/ssa