土耳其上空的双月八字曲线
(原标题: A Double Lunar Analemma over Turkey)
2022-10-10
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八字曲线是你在一年中每天同一时间标记太阳位置时得到的8字形曲线。但要想描绘出月球的8字曲线，关键是要再等一段时间。平均来说，月球每天回到天空中相同的位置要晚50分29秒。所以在连续几天的50分29秒后拍摄月球。在一个月历或阴历月里，由于月球倾斜和椭圆的轨道，它的实际位置会发生变化，因此它会画出一条类似八月的曲线。由于这张特色图片是在两个多月的时间里拍摄的，它实际上显示了一个双月球八字曲线。新月的月相太细太暗，无法捕捉到新月周围的景象。这位坚持不懈的天文摄影师选择的两个月是在7月和8月的好天气期间，地点是土耳其的开塞利
查看原文解释
An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. But the trick to imaging an analemma of the Moon is to wait bit longer. On average the Moon returns to the same position in the sky about 50 minutes and 29 seconds later each day. So photograph the Moon 50 minutes 29 seconds later on successive days. Over one lunation or lunar month it will trace out an analemma-like curve as the Moon's actual position wanders due to its tilted and elliptical orbit. Since the featured image was taken over two months, it actually shows a double lunar analemma. Crescent lunar phases too thin and faint to capture around the New moon are missing. The two months the persistent astrophotographer chose were during a good stretch of weather during July and August, and the location was Kayseri, Turkey
© Betul Turksoy