Posted by BC on August 9th, 2008
For those of you who like to observe the many features on the Moon, how many of you have seen the “X”? As you know the appearance of lunar features change as the Moon cycles through the phases. The “X” is one of those features, much like the Straight Wall, that is visible only during certain times.
The Lunar X is near Crater Werner in the Moon’s southern hemisphere, and it is visible for only a couple of hours as the Moon is a few hours past First Quarter phase. The particular shadow is created only when the Sun angle is just right as it passes across the lunar terrain.
The next time to see the “X” on the Moon is UT 0945 07Sept2008.
The Lunar X Files: a fleeting vision near crater Werner by David M.F. Chapman explains more.