Performance specification

The following performance criteria have been set as targets for SuperCOSMOS.

• Measurement area 0.5m square.

• Absolute accuracy m, defined as the accuracy with respect to a perfectly uniform rectilinear Cartesian coordinate system.

• Repeatability m, defined as the largest variation in the absolute errors when measurements taken on different days are compared: it is this performance criterion which is most important for obtaining accurate astronomical results.

• Dynamic range , defined as the ratio of the highest transmission value measurable on a UKST plate to the lowest transmission level measurable at a signal/noise ratio of unity.

• Scattered light surface brightness times the maximum measurable transmission value.

• Sampling interval m.

• Resolution (FWHM of point-spread function, including the effects of finite pixel size) m.

• Time needed to digitise a UKST plate < 2 hours.

• Time needed to analyse a UKST plate < 2 hours.