  We present techniques for obtaining presision astrometry using old
photographic plates from assorted large-aperture reflectors in combination with
recent CCD Mosaic Imager frames. At the core of this approach is a
transformation of plate/CCD coordinates into a previously constructed
astrometric reference frame around the open cluster NGC 188. Our primary result
is a new catalog of proper motions and positions for 7812 objects down to V=21
in the 0.75 square degree area around NGC 188. The precision for well-measured
stars is 0.15 mas/yr for proper motions and 2 mas for positions on the system
of the Tycho-2 catalog. The sum of membership probabilities indicates that NGC
188 contains 1050 stars down to V=21. Comprehensive lists of the candidate blue
stragglers and red giants substantially enlarge the number of such stars known
in NGC 188. We have also obtained a small correction to the proper motions from
the mean `motion' of background galaxies. (Abridged)
