Observation environment of the Bohyunsan Optical Astronomy Observatory(BOAO) has been examined using various statistical data including real observation times versus allocated times and seeing statistics. The data have been collected from the observation logs of the 1.8m telescope in the period 1998 - 2004. New criteria have been set up to calculate a more realistic observation efficiency of the observatory. The new statistical analysis based on the new criteria gives the overall observation efficiency of BOAO as 38.6%, that is equivalent to 115.8 observable nights out of 300 allocatable nights. The seeing statistics shows that the mean seeing measured at the focal images is 2".3. The present study of the observation environment of BOAO suggests that differential photometry and spectroscopy should be preferred modes of observation to maximize the productivity of BOAO.

• 박윤호(한국천문연구원, 부산대학교 지구과학과) | YOON-HO PARK (Korea Astronomy Observatory, Department of Earth Science, Pusan National University)
• 박병곤(한국천문연구원) | BYEONG-GON PARK (Korea Astronomy Observatory)
• 안홍배(부산대학교 지구과학과) | HONG-BAE ANN (Department of Earth Science, Pusan National University)