同时也标注了另一个日子，6月6号，这一天将发生金星凌日。

They also marked another date, June 6, the transit of Venus across the sun.

这是一个问题，所有的第十八和许多第十九世纪的天文学家面临当他们被派去观察金星凌日在偏远的地方。

This is a problem all of the eighteenth and many of the nineteenth century astronomers faced when they were sent out to observe the transit of Venus in far flung places.

IAU的金星凌日工作小组并力促在过去曾观测凌日的地点设立纪念碑。

The IAU's Working Group on Transits of Venus is encouraging the placement of memorial plaques at the sites of previous transit observations.