TASS Mark IV photometric survey of the northern sky

The Amateur Sky Survey ( TASS) is a loose confederation of amateur and professional astronomers. We describe the design and construction of our Mark IV systems, a set of wide-field telescopes with CCD cameras that take simultaneous images in the V and I-C passbands. We explain our observational procedures and the pipeline that processes and reduces the images into lists of stellar positions and magnitudes. We have compiled a large database of measurements for stars in the northern celestial hemisphere with V-band magnitudes in the range 7 < V < 13. This paper describes data taken over the 4 year period beginning in 2001 November. One of our results is a catalog of repeated measurements on the Johnson-Cousins system for over 4.3 million stars.