On June 5th-6th 2012, a transit of Venus across the disk of the Sun takes place，which was viewed at Yunnan observatory by ONSET(Optical-NIR Solar Eruption Explore Telescope)developed by NIAOT。

　  Venus transits are very rare events which last 6.5 hours this time。It can not be observed again untill 2117。

all-disc solar image at 360nm by ONSET ("black drop"　Venus)

all-disc solar image at 425 nm by ONSET ("black drop"　Venus)

all-disc solar chromosphere image at 656.3 nm by ONSET ("black drop"　Venus)