  The detection of transiting extrasolar planets requires high-photometric
quality and long-duration photometric stellar time-series. In this paper, we
investigate the advantages provided by the Antarctic observing platform Dome C
for planet transit detections during its long winter period, which allows for
relatively long, uninterrupted time-series. Our calculations include limiting
effects due to the Sun and Moon, cloud coverage and the effect of reduced
photometric quality for high extinction of target fields. We compare the
potential for long time-series from Dome C with a single site in Chile, a
three-site low-latitude network as well as combinations of Dome C with Chile
and the network, respectively. Dome C is one of the prime astronomical sites on
Earth for obtaining uninterrupted long-duration observations in terms of
prospects for a high observational duty cycle. The duty cycle of a project can,
however, be significantly improved by integrating Dome C into a network of
sites.
