Though it is said that the two witness must observe the new moon becoming a crescent in the western sky, this is Jewish oral tradition according to, Rosh Hashanah, Chapter 2, Mishnah 6. This would be a waxing crescent moon. Since this moon cannot be seen in Israel until Sunday, some have questioned the legitimacy of Rosh Hashanah being on September 23.
 
However, there is also tradition that the new moon could be sanctified by watching for the disappearing moon or waning crescent according to Chapter 3, Mishnah 1.
 
In any case the new moon is to be determined by two witnesses, but the key is that the moon has to be new to start the month. A new moon is concealed. It is hidden (like we will be in the rooms/mansions). To have it be a visible crescent moon before declaring the day the first of the seventh month would be a violation of it being a new moon. That is because it would not be new anymore.
 
In Leviticus 23:24 it speaks only of the first of the month. Psalm 81:3 (KJV is correct) speaks of the new moon and there are many passages mentioning the new moon and the festivals, but no crescent moons are found in context.
 
On September 22, 2006 or this Friday, there will be a solar eclipse at 11:40 am universal time. This of course removes all doubt on whether the moon is new. Four hours later in Israel it is sunset and the start of Tishri 1. The moon will actually remain hidden from the vantage point of Israel for two days--September 23-24. It should be easily visible at sunset September 24.
 
So what is the hour? Some have said midnight (ten virgins) and others noon (Amos 8 and Micah 7). Noon in Israel (1pm Daylight) would make Rosh Hashanah mostly worldwide at that time, but I don't pretend to know. Maybe some others have other ideas to share.
 
Side notes:
 
While looking into the sighting of the first crescent moon, it was found that the first possible place to see it would be just 4 degrees east of Perth, Australia at sunset September 23. The interesting part of this is that in Israel it would be 1 pm daylight savings time or noon at proper standard time. So globally the new moon would be over at true noon in Israel.
 
Islam looks for the first crescent and that is why Ramadan is September 24.
 
http://www.crescentmoonwatch.org/nextnewmoon.htm
 
Daniel Matson
http://Jesus2006.org
 
And thank you for the thank yous!
 
Today is world peace day for the added irony...