The SuperCOSMOS data held in the SSA primarily originate from scans of Palomar and UK Schmidt blue, red and near-IR southern sky surveys. The ESO Schmidt R (de c -17.5) surveys have also been scanned and provide a 1st epoch red measurement. Further details on the surveys, the scanning process and the raw parameters extracted can be found on the further information link. The SSA is housed in a relational database running on Microsoft SQL Server 2000. Data are stored in tables which are inter-linked via reference ID numbers. In addition to the astronomical object catalogues these tables also contain information on the plates that were scanned, survey field centre s and calibration coefficients. Most user science queries will only need to access the SOURCE table or to a lesser extent the DETECTION table.