拉斯坎帕纳斯天文台上空的波状层积云

2024年11月19日

Undulatus Clouds over Las Campanas Observatory
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN); h/t: Alice Allen

Explanation: What’s happening with these clouds? While it may seem that these long and thin clouds are pointing toward the top of a hill, and that maybe a world-famous observatory is located there, only part of that is true. In terms of clouds, the formation is a chance superposition of impressively periodic undulating air currents in Earth’s lower atmosphere. Undulatus, a type of Asperitas cloud, form at the peaks where the air is cool enough to cause the condensation of opaque water droplets. The wide-angle nature of the panorama creates the illusion that the clouds converge over the hill. In terms of land, there really is a world-famous observatory at the top of that peak: Carnegie Science‘s Las Campanas Observatory in the Atacama Desert of Chile. The two telescope domes visible are the 6.5-meter Magellan Telescopes. The featured coincidental vista was a surprise but was captured by the phone of a quick-thinking photographer in late September.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Tomorrow’s picture: flight day 6

拉斯坎帕纳斯天文台上空的波状层积云
影像提供与版权: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN); h/t: Alice Allen

说明: 这些云发生了什么事？这些既长又薄的云看似指向山顶，而那里或许座落着世界著名的天文台，但这个陈述只有部分是真的。关于云的部分，这些云是地球低层大气中，周期性波状气流偶然产生的现象。波状层积云是糙面云的一种，形成于空气够冷足以凝结出不透光水滴的波峰处。它们之所以看似会聚在山顶上方，则是全景广角效应所造成的幻觉。在地面的那座山顶上，的确是有一座世界闻名的天文台，它是位于智利阿塔卡马沙漠的卡内基科学院之拉斯坎帕纳斯天文台。影像中所见的2个望远镜圆顶，为6.5米口径的麦哲伦望远镜。这片意外出现的景观，是在今年9月底由一位反应迅速的摄影者用手机拍下的。（undulatus clouds 波状层积云；asperitas clouds 糙面云）