Title: will be set by the publisher Editors: will be set by the publisher EAS Publications Series, Vol.?, 2010 PHOTOMETRIC QUALITY OF DOME C FOR THE WINTER 2008 FROM ASTEP SOUTH

• Main Authors: Nicolas Crouzet, Tristan Guillot, Karim Agabi, Yan Fanteï-caujolle, Francois Fressin, Jean-pierre Rivet, Erick Bondoux, Lyu Abe, Alain Blazit, Serge Bonhomme, Carole Gouvret, Djamel Mékarnia, Francois-xavier Schmider, Franck Valbousquet, The Astep Team
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Concordia Station; South Pole; The Antarctic; Antarc*; Antarctica; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.406.4923; http://hal.archives-ouvertes.fr/docs/00/45/65/13/PDF/Crouzet_C.pdf

Planets in the South pole field, from the Concordia station, Dome C, Antarctica. The instrument consists of a thermalized 10 cm refractor observing a fixed 3.88 ◦ x 3.88 ◦ field of view to perform photometry of several thousand stars at visible wavelengths (700-900 nm). The first winter campaign in 2008 led to the retrieval of nearly 1600 hours of data. We derive the fraction of photometric nights by measuring the number of detectable stars in the field. The method is sensitive to the presence of small cirrus clouds which are invisible to the naked eye. The fraction of night-time for which at least 50 % of the stars are detected is 74 % from June to September 2008. Most of the lost time (18.5 % out of 26%) is due to periods of bad weather conditions lasting for a few days (”white outs”). Extended periods of clear weather exist. For example, between July 10 and August 10, 2008, the total fraction of time (day+night) for which photometric observations were possible was 60%. This confirms the very high quality of Dome C for nearly continuous photometric observations during the Antarctic winter.