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Database Overview - Tables

The DETECTION table contains individual plate detections for every scanned plate in the SSA. Each scanned plate in the SSA results in a pixel map. This map was processed using standard software (known as Image Analysis Mode, or IAM, software) to produce a list of parameterised detections on each plate. This table contains all the attributes for each detected object. The attribute set consists of the standard 32 IAM parameters plus calibrated photometry, spatial index quantities and ID numbers.

SOURCE contains merged sources for every field in the SSA. Each field within the SSA is covered by four plates in passbands B, R and I with R being covered twice at different times. This results in four-plate multi-colour, multi-epoch data which are merged into a single source catalogue for general science exploitation. This table contains the associated merged records created from the objects in DETECTION, along with a full astrometric solution (including proper motions) computed from the available position measures. The most useful subset of image morphological descriptors are also propagated into this table for ease of use. Many of the parameter names in SOURCE are appended with the letters B, R1, R2 or I this indicates which survey the parameter refers to.

B	= UK Schmidt blue (Bj) survey
R1	= ESO Schmidt or Palomar POSS-Ie red survey
R2	= UK Schmidt red survey
I	= UK Schmidt near-InfraRed survey

SOURCE and DETECTION are linked via the parameter sourceID in DETECTION and the parameters objIDB, objIDR1, objIDR2 and objIDI in SOURCE.