The Faint Sky Variability Survey I: Goals and data reduction process
  The Faint Sky Variability Survey is aimed at finding photometric and/or astrometric variable objects in the brightness range between 16<V<24 on timescales between tens of minutes and years with photometric precisions ranging from 3 millimagnitudes for the brightest to 0.2 magnitudes for the faintest objects. An area of ~23 square degrees, located at mid and high Galactic latitudes, has been covered using the Wide Field Camera on the 2.5m Isaac Newton Telescope on La Palma. Here we describe the main goals of the Faint Sky Variability Survey and the data reduction process. 
Paul J. Groot, Paul M. Vreeswijk, Mark E. Huber, et al