A few days ago, the thin crescent Moon passed close to the planet Venus in the evening twilight sky. Conjunctions such as this repeatÂ at roughly one-month intervals so this is not a rare occurrenceâ€”just a beautiful one.
The crescent Moon is ~2.4%Â illuminated by the direct light of the Sun; the remainder of the Moon is lit by Earthshine which is bright enough to show detail on the shadowed face of the Moon. Leonardo da Vinci explained the phenomenon in the early 16th century when he realized that both Earth and the Moon reflect sunlight at the same time. Light is reflected from Earth to the Moon and back to Earth as earthshine.
During the late spring and early summer the waxing crescent Moon will align with the long axis of Lake Mary. The end result is that as the Moon sets it will have a long reflection on the lake. So I found myself on the east end of Lake Mary a few days ago waiting for the clouds to clear and the Moon to put on a show.
While waiting I shot several images of the lake using slow shutter speeds. This produces very smooth waterâ€”although it may appear somewhat unrealistic. No matter. I was having fun.
Here is an 8-second exposure:
Finally, the clouds cleared and the Moon appeared with its reflection in the water.
The crescent Moon is about 6% illuminated by the direct light of the Sun; the remainder of the Moon is lit by Earthshine which is bright enough to show detail on the shadowed face of the Moon.