希腊神庙后方的蛾眉月

2023年2月28日

Crescent Moon Beyond Greek Temple
Image Credit & Copyright: Elias Chasiotis

Explanation: Why is a thin crescent moon never seen far from a horizon? Because the only geometry that gives a thin crescent lunar phase occurs when the Moon appears close to the Sun in the sky. The crescent is not caused by the shadow of the Earth, but by seeing only a small part of the Moon directly illuminated by the Sun. Moreover, the thickest part of the crescent always occurs in the direction of the Sun. In the evening, a thin crescent Moon will set shortly after the Sun and not be seen for the rest of the night. Alternatively, in the morning, a crescent Moon will rise shortly before the Sun after not being seen for most of the night. Pictured two weeks ago, a crescent moon was captured near the horizon, just before sunrise, far behind remnants of the ancient Temple of Poseidon in Greece.

Tomorrow’s picture: flaming comet

希腊神庙后方的蛾眉月
图像提供与版权: Elias Chasiotis

说明: 为何纤细的蛾眉月总是离地平线不远？因为在几何上，天空中的月亮只有出现太阳附近时，才会带着纤细的蛾眉相。蛾眉月并非是地球的影子所造成的，而是只有一小部分的月面受到太阳的直接照射。此外，蛾眉月最厚的部分总是指向太阳。在傍晚时，一轮纤细的蛾眉新月在日落后不久也随着西沉，然后彻夜不得见。而出现于早晨的蛾眉残月，则在大半夜未见后赶在日出前升起。在这幅摄于2星期前的图像里，在即将日出的地平线附近，希腊波塞冬神庙遗址的远后方悬着一抹弯弯的蛾眉残月。

明日的图片: flaming comet