I know I am going to be sorry for posting this, but I was startled by this thread.
It could not possibly be a physical phenomenon, but MAYBE it has something to do with perception.
I am well versed in observing nature, including the skies. (I used to be a very active mountaineer and have beeninvolved in a few rescue operations,
which you don't get to do if you're a bumpkin who knows nothing about nature, or if you do, you don't last long.) I am usually able to tell the time
of day with a 5 - 10 minutes of margin by simply looking at the sky.
Still, yesterday, July 19, I was startled by the position of the Moon. It was a first. Something like that never ever happened to me before in my
life. But I was so startled by its position that I went out and had a good look at it, then returned inside and checked Stellarium (which I had been
using from before it even came out "publicly").
All appeared to be in order. But I could have sworn that the Moon was in the wrong place compared to the previous evening, when I observed it, as I do
every day when I am at home, from the exact same spot in my studio. (Yes, of course I know its position progresses compared to each previous day,
naturally; that was taken into account.)
Like I said, it was the first time in my entire life that anything about the position of celestial bodies took me by surprise. And I cannot account
for the apparent "anomaly", of course not. I only know it could not have been something physical, but the fact that this happened to you on the same
and only evening that I observed an "anomalous"position struck me as very odd, so I just had to say something.
Did something affect our perception and visual memory?
I have no idea what or how, but it's the only explanation I could think of.
edit on 20-7-2011 by AdAstra because: (no reason given)
That might certainly prove more profitable for you. 
It bugged me so much, I went for a walk every night looking for it 
