DSLR and iPhone images
Lunar X and Lunar V - iPhone
The Lunar "X" is a transient optical feature of the Moon that occurs for about 4 hours near First Quarter phase of the Moon. Because the Earth is not always in the same place when the Moon is in this ideal sunlight location, not everywhere on Earth will always see the Lunar "X" phenomenon every month. However, it occurs frequently enough for most areas that it can be seen, on average, every few months. And it's a bright enough feature that it can even be seen in daylight - if you know when and where to look.Somewhat less well-known is the Lunar V. This sunlit feature is similar to the X in size, but is visible for quite a bit longer after the "X" has dissolved into the background craters. Created by sunlight striking the tops of the crater Ukert and ridges nearby, the "V" shape is slightly larger than the "X", though quite a bit further north, just south of the small Mare Vaporum. As the "X" becomes less prominent over time, the "V" still maintains a distinct shape and may also be viewed with most any small telescope or tripod-mounted binoculars.