Shalom everyone!

My name is Christopher, and I've written a document (posted below) which underlines the major factors for calculating the proper dates for Passover, and thusly, all of the rest of Yahweh's appointed Feasts throughout the year. (as well as I understand it)
**Please note that as I live Western Canada, I've listed the appropriate timezone conversion for my local area.**

The proper determining of the Passover date is based upon a number of factors:

1.The barley (in Jerusalem!) must be ripened to a certain point (known as “Abib”) in order for it to be ready to harvest at the appropriate time to serve for the Wave Sheaf offering; Because of this, the New Moon which signals the beginning of the “month of the Abib” (also known as Nisan) must come after the “Abib” stage of ripeness has been reached. The New Moon date is to be determined by calculation of the sunset-to-sunset period during which the New Moon conjunction (“hidden/dark” phase) is to occur (in Jerusalem*); and confirmed by the reported sighting (by 2 or more witnesses) of the visible crescent of the “New” Moon (which should be able to be seen shortly after sunset on the day following the conjunction “day”).

2.The Feasts of Passover (14 Nisan) & the Days of Unleavened Bread (15 – 21 Nisan) cannot begin during the “winter” season; In other words, Passover can only fall after the Vernal (“Spring”) Equinox.

3.The Passover date (14 Nisan) coincides with the FULL MOON.

*Note: Jerusalem Time is 2 hours ahead of Universal Time. – Adjust to compensate for your local time.

If we take these factors into account and apply them to the following “known data” for this year (2008):

Known data: **

1.The Vernal Equinox for 2008 falls on March 20, 2008 @ 05:48 UT (Universal Time), or 10:48pm MST (Mountain Standard Time) on March 19, 2008 for those in Edmonton, AB and area. This means that the “day” of the Vernal Equinox will occur during the sunset-to-sunset period of March 19th – 20th, 2008.

2.The earliest prospective Spring harvest of the Winter-planted barley in Jerusalem is supposedly March 26, 2008; this is based on ideal weather conditions. This means that the New Moon which comes after this date will signify the start of the “Month of the Abib”.

3.The New Moon which comes after March 26, 2008 is expected to occur on April 6, 2008 @ 03:55 UT (Universal Time), or 8:55pm MST (Mountain Standard Time) on April 5, 2008 for those in Edmonton, AB and area.
This means that the “day” of the New Moon conjunction will occur during the sunset-to-sunset
period of April 5th – 6th, 2008.

*Note: If the New Moon conjunction “day” serves as a starting point (or “day 0”) for the month, and the following “day” is counted as “day 1”, then the count to the 14th “day of the moon” (or “day of the month”, as referenced in Scripture) will coincide with the Full Moon.

4.The Full Moon conjunction during April 2008 is expected to occur on April 20, 2008
@ 10:25 UT (Universal Time), or 3:25am MST (Mountain Standard Time) on April 20, 2008 for those in Edmonton, AB and area. This means that the “day” of the Full Moon conjunction
will occur during the sunset-to-sunset period of April 19th – 20th, 2008.

Conclusion:

The Passover (14 Nisan) & Days of Unleavened Bread (15 – 21 Nisan) dates for 2008 are:

Passover: sunset-to-sunset April 19th – 20th, 2008.
Night To Be Much Observed: Begins the "evening" (sunset) of April 20th, 2008.
Days of Unleavened Bread: sunset April 20th, 2008 to sunset April 27th, 2008.