Well, I'm not a Muslim, but I've played one in live games... :-)
As I understand it, the reason for the variations in the start of Ramadan are that the Muslim months are lunar, and begin specifically the first night that the crescent moon is sighted by two trustworthy Muslim witnesses (or one, by some interpretations.) Astronomical calculations may be used as a guide for when to look, but these alone are not supposed to determine the date.
In theory, the testimony of two trustworthy witnesses anywhere in the world is supposed to apply to all once they get word of it, but it appears that in practice, imams in various countries declare the beginning of Ramadan for that country. This doesn't seem to be a big deal, because the texts talk about starting it the day you first see the crescent, even if it's been obscured by the weather and you know it happened on an earlier day (if you don't hear about it from someone else, that is.) So the situation seems to be that you should trust a call from anywhere in the world, but there's a long pre-mass communication tradition of local decisions, and everyone observing Ramadan faithfully is more important than petty disagreements.
I understood the lunar-sighting bit, and the reason that when I looked it up last week the web sites I found said, "Ramadan is predicted to start on...", but as of the time I edited my quotes-file, I was still confused as to when it had actually started here (if there's a single authority for U.S. Muslims to listen to ... if there's more than one and they disagree, then I guess I'll have to remain as confused as the man with two wristwatches).
What I don't understand yet is how one schedules appointments beyond the end of the current month in that calendar. I don't recall seeing that addressed on the calendar web sites I've read so far, and I keep forgetting to ask.
Yeah, I read in the Sunday paper that Saudi Arabia and others declared that Ramadan will start on Sunday, and Egypt declared it will start on Monday. I'm equally confused by that; according to the rules I read, I don't see how they can say in advance when it will start.
As to the future months, I'm not sure that the start of calendar months in general depends on sighting the new moon, or just the beginning and end of the Ramadan fast. (Some of the quotes from the texts I saw indicated, not surprisingly, that they well understood that the next moon would come 29-30 days after the previous one, and for non-holy months, the sighting of the moon functioned more as a resynchronizing mechanism. But I'm not at all sure about that.)
Ramadan
As I understand it, the reason for the variations in the start of Ramadan are that the Muslim months are lunar, and begin specifically the first night that the crescent moon is sighted by two trustworthy Muslim witnesses (or one, by some interpretations.) Astronomical calculations may be used as a guide for when to look, but these alone are not supposed to determine the date.
In theory, the testimony of two trustworthy witnesses anywhere in the world is supposed to apply to all once they get word of it, but it appears that in practice, imams in various countries declare the beginning of Ramadan for that country. This doesn't seem to be a big deal, because the texts talk about starting it the day you first see the crescent, even if it's been obscured by the weather and you know it happened on an earlier day (if you don't hear about it from someone else, that is.) So the situation seems to be that you should trust a call from anywhere in the world, but there's a long pre-mass communication tradition of local decisions, and everyone observing Ramadan faithfully is more important than petty disagreements.
I thought this was a pretty good summary.
Re: Ramadan
What I don't understand yet is how one schedules appointments beyond the end of the current month in that calendar. I don't recall seeing that addressed on the calendar web sites I've read so far, and I keep forgetting to ask.
Re: Ramadan
As to the future months, I'm not sure that the start of calendar months in general depends on sighting the new moon, or just the beginning and end of the Ramadan fast. (Some of the quotes from the texts I saw indicated, not surprisingly, that they well understood that the next moon would come 29-30 days after the previous one, and for non-holy months, the sighting of the moon functioned more as a resynchronizing mechanism. But I'm not at all sure about that.)