We know that the X is easy to see at night, during lunar sunrise (waxing phases) - but what about in daylight hours, during lunar sunset (waning phases)? I was curious about this a number of years ago, and decided to find out.
The first favorable date was August 15th 2006. Luna had risen at 11:00PM the previous night, transited at 7:00AM that morning, and would set at 2:00PM that afternoon. I wasn't able to get out till 11:00AM though, and she was already sliding down toward the western horizon. But thankfully there was enough time to get what i needed before she slipped into the turbulent 30° airmass. It would have been ideal to do this when she was high in the sky with the X directly on her terminator, but we lunatics have to take what we can get, and be happy with it.
Here's an image from that day, placed below another image of mine (not the same one that was on LPOD, though) - the images are comparably sized in order to make identification easier. Although the daylight image is poor at best, the shadowplay appears to suggest that the X is sloping slightly towards the east limb (right side in the images), and the X's appearance might very well disintegrate as the terminator got closer. I never found out, but it was a fun observation anyway.
Oddly enough, i never went back to look at the X during the daytime again and it made me wonder if anyone here in the LunieBin might be interested in making it an ongoing project - i think it would be a lot of fun to take things to the next level. If there's any interest, someone could (thanks in advance! ) post a list of available dates below. It'll give us something to start with, and as time passes we could bump the thread up as needed in order to keep everything in one discussion.
How about it?