  Residuals of a conventional plate adjustment of 5,687 plates of the Second
Cape Photographic Catalogue (CPC2) using the Southern Reference Star (SRS)
Catalog were analyzed to search for systematic errors depending on the location
of the star images on the plate. Even after correcting for third order optical
distortion, such coordinate depending systematic errors, hereafter called field
distortion pattern (FDP), were detected which are nearly constant with respect
to plate epoch, location in the sky and apparent brightness of the stars. The
mean amplitude of these field distortions was found to be 57 milliarcseconds
(mas), which is $0.57 \ \mu m$ on a plate. Due to the favorable 4--fold overlap
observing principle of the CPC2, the effect on the mean catalog position is
only a fraction of that. But the FDP affects a block adjustment (BA) of the
entire set of data on a 100 mas level at the border of the CPC2 sky coverage. A
comparison with FDP's found in other projects was made and physical reasons for
the FDP were investigated. Publication of a new release of the CPC2 is planned
after the Hipparcos Output Catalog becomes available in 1996.
