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美国国家航空航天局NASA每日一图(天文)-2017年8月12日

2017 August 12

A Day in the Life of a (mostly) Human Sundial 
Video Credit & Copyright: Astronomie-AG, Progymnasium Rosenfeld, Till Credner, AlltheSky.com
Explanation: Have you ever wanted to be a gnomon? Of course, a gnomon is the tall part of a sundial that casts a shadow. The gnomon's shadow moves as the Sun moves across the sky, indicating time by the shadow's position on the dial face. So on July 19th, the Astronomy Group of the Progymnasium Rosenfeld created a human sundial, each participant patiently playing the role of the gnomon for 10 minutes. In this timelapse video of their temporal voyage of discovery, one image was taken every 20 seconds from 8 am until 4 pm Central European Summer Time. Drawn on the ground are the dial hour marks calculated to show the local time for that specific date. Behind, the tower clock offers a time check. Can you find the local time of solar noon? (Hint: At solar noon the Sun is on the meridan.) The persistent group plans a repetition of the human sundial performance next winter to compare the length of the day and the altitude of the Sun.

2017年8月12日

人生日常生活中的一天
视频信用与版权所有:Astronomie-AG,Progymnasium Rosenfeld,Till Credner,AlltheSky.com
说明:你有没有希望成为一个gnomon?当然,一个日常用品是日the高耸的阴影。随着太阳在天空中的移动,侏儒的阴影正在移动,表明时间是阴影在表盘上的位置。所以7月19日,罗森菲尔德天文学小组创建了一个人类日ial,每个参与者都耐心地发挥了侏儒的作用10分钟。在这段瞬间发现的视频中,每20秒钟从中午欧洲夏季时间上午8点至下午4点拍摄一张图像。在地面绘制的是表示该特定日期的当地时间的计时表。在后面,塔钟提供时间检查。你能找到中午的当地时间吗? (提示:太阳中午太阳在子午线上。)持续的组织计划在冬天重复人类日ial表演,以比较当天的长度和太阳的高度。

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