  Observing sites at the East-Antarctic plateau are considered to provide
exceptional conditions for astronomy. The aim of this work is to assess its
potential for detecting transiting extrasolar planets through a comparison and
combination of photometric data from Antarctica with time series from a
midlatitude site.
  During 2010, the two small aperture telescopes ASTEP 400 (Dome C) and BEST II
(Chile) together performed an observing campaign of two target fields and the
transiting planet WASP-18b. For the latter, a bright star, Dome C appears to
yield an advantageous signal-to-noise ratio. For field surveys, both Dome C and
Chile appear to be of comparable photometric quality. However, within two
weeks, observations at Dome C yield a transit detection efficiency that
typically requires a whole observing season in Chile. For the first time, data
from Antarctica and Chile have been combined to extent the observational duty
cycle. This approach is both feasible in practice and favorable for transit
search, as it increases the detection yield by 12-18%.
