The Walther Sunset Ray appears at 0319UT. Located in the Walther crater this is a special treat that occurs monthly for a matter of a few hours. On the western rim of the crater there’s a notch and when the Sun is setting low on the lunar horizon (when the crater is near the terminator) light penetrates the notch, creating a vast triangle or “V” shaped light ray across the craters floor that ends as it illuminates the central peak of the crater.
This ray is rarely viewable from the UK and is top of my list of lunar targets.
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