The »golden handle« of the Moon
When the sunlight appears on the Moon’s surface in a flat angle, interesting lighting effects are created, due to the mountains and valleys, which can be observed quite well from the Earth. A well-known effect is the so called »golden handle«. This is when the Jura Mountains (»Montes Jura«) are illuminated 4 to 5 days before the full moon and appear as a bright arc, in front of the still darkened Sea of Showers (»Sinus Iridum«) of the Mare Imbrium. This is reinforced by the fact that the boundary of light and shadow, which is called »terminator«, runs directly through this area.
Already Galileo Galilei (1564–1642) knew of the »golden handle« and used his observations to estimate the altitude of the moon mountains – a fascinating thought, when you imagine that you can look over his shoulder, while doing it.
It is always worthwhile to take a good look at our Moon and the interesting details on its surface. How pleasantly small our earthly problems become …