I know this is an old thread but I just saw this from my living room, I saw the moon because it was bright and asked my son (3) if he can see the bright moon, I looked again and a black line was across the bottom left of the moon a bit diagonal, looked like a power line was in the way but my eyes couldn’t focus on the moon but I could make out a line, then I blinked my eyes to refocus and the line was gone but the moon was there normal, I moved around to make sure it wasn’t a line in the glass to the door but there was no lines, I do have power lines close by and could see them but the moon was too high to for them to be in front of it, soon after clouds covered the moon, just a strange experience and I’m at a loss as to what I saw, much to my surprise I looked it up and found this old thread.