The rationale for observing the Sun from Antarctica has traditionally been the need for long, uninterrupted time-series of data (Fossat, Grec and Pomerantz 1981, Duvall et al. 1991), in the framework of studies of solar oscillations. State-of-the-art helioseismology, however, begun to take advantage of the deployment of networks of observing stations in more accessible sites around the globe (GONG, IRIS, BISON, TON), or of data from satellite experiments (SOHO). These experiments provide full-disk solar images whose best spatial resolution is 2"/pixel, and the fastest acquisition rate is typically one minute. The fact that the South Pole site, where most helioseismological campaigns have been carried out, is not exceptional in terms of quality and stability of the seeing, explains why Antarctica seems to have lost much of its appeal for high-quality solar research.
Very recently, other Antarctic sites have been suggested to be advantageous for astronomical research. In particular, the Dome C site, where an Italian-French base is being built, seems especially promising. Preliminary site test campaigns at Dome C demonstrate that the atmosphere there is very stable, due to a combination of several favourable conditions, including its high elevation (3280 m a.s.l.) and the near absence of wind (in average below 3 km/s) (Valenziano and Dall'Oglio 1999). Thus, Dome C is probably one of the best sites in the world, if not the best, for long-duration, high-resolution astronomy, especially in the infrared.
Several aspects of solar research could also take advantage of such characteristics. While high-resolution solar observations (down to subarcsecond values) are becoming increasingly common, especially through the use of adaptive optics techniques, telescopes providing very high resolution images guarantee their best performances only for (at most) a few hours per day. Thus, long-duration, continuous high-resolution observations, are currently impossible to attain from ground-based sites.
In principle, space-borne observatories could address such needs, over the full electromagnetic spectrum. Nevertheless, an Antarctic site, however remote, allows a much greater flexibility in managing, modifying, and upgrading telescopes and instrumentation, in comparison with any space project. Thus, the Dome C, with a combination of great stability and transparency of the atmosphere, could be now considered unique among ground-based sites for solar observations.