Excellent daytime seeing at Dome Fuji on the Antarctic plateau

TL;DR

Dome Fuji on the Antarctic plateau exhibits excellent daytime astronomical seeing with median values around 0.52 arcseconds, and the surface boundary layer can be as low as 11 meters, indicating its potential as a prime observational site.

Contribution

This study provides the first detailed measurements of daytime seeing and boundary layer height at Dome Fuji, confirming its suitability for astronomical observations.

Findings

Median seeing of 0.52'' observed during the day

Occasional periods of seeing below 0.2''

Surface boundary layer as low as ~11 meters

Abstract

Context. Dome Fuji, the second highest region on the Antarctic plateau, is expected to have some of the best astronomical seeing on Earth. However, site testing at Dome Fuji is still in its very early stages. Aims. To investigate the astronomical seeing in the free atmosphere above Dome Fuji, and to determine the height of the surface boundary layer. Methods. A Differential Image Motion Monitor was used to measure the seeing in the visible (472 nm) at a height of 11 m above the snow surface at Dome Fuji during the austral summer of 2012/2013. Results. Seeing below 0.2'' has been observed. The seeing often has a local minimum of ~0.3'' near 18 h local time. Some periods of excellent seeing, 0.3'' or smaller, were also observed, sometimes extending for several hours at local midnight. The median seeing is higher, at 0.52''---this large value is believed to be caused by periods when the telescope was within the turbulent boundary layer. Conclusions. The diurnal variation of the daytime seeing at Dome Fuji is similar to that reported for Dome C, and the height of the surface boundary layer is consistent with previous simulations for Dome Fuji. The free atmosphere seeing is ~0.2'', and the height of the surface boundary layer can be as low as ~11 m.