Modern photographic catalog work: Aspects of observing techniques and reduction methods

The consequent application of present optical technology for the construction of substantially improved instrumentation in photographic astrometry and the application of rigorous reduction techniques provide all means for the construction of new, global position catalogs with a precision of a few 0.01 arcsec. At the same time the limiting magnitude of those catalogs can be extended to about 17 without decreasing positional accuracy. High speed measuring machines combined with real time reductions and storage on optical disks can handle the huge amount of information on a single plate. The throughout application of block adjustment reduction of global and hemisphere covering catalogs can provide a rigid stellar net which can be adjusted for the first time to a quasar based future reference frame directly. Instrumental requirements and optimal reduction techniques for achieving this goal are discussed.