>>asim+(OP)
I was unaware until this year that it was based on when the moon was _sighted_, not just on a conventional lunar calendar. This leads to very short notice public holidays in a couple of countries AIUI.
>>rsynno+Xv1
I didn't either, but my boss (who is Turkish) mentioned that there was middle-eastern countries where holidays were not totally predictable. This was in the context of some work-day report which had funky options.