home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Media Share 9
/
MEDIASHARE_09.ISO
/
progmisc
/
dblib201.zip
/
SHANA.TXT
< prev
next >
Wrap
Text File
|
1993-03-29
|
4KB
|
59 lines
*-- SHANA.TXT
*-----------------------------------------------------------------------------
*-- Author's note about Hebrew-calendar functions:
*-- My main source for these algorithms was "The Comprehensive Hebrew
*-- Calendar" by Arthur Spier, Third Revised Edition, Philipp Feldheim Inc.,
*-- Spring Valley, NY, 1986, but I never could have understood it without
*-- first, the fine materials given me by Dave Krajcar, ("Altsol"), of
*-- Alternative Solutions, Inc., at considerable personal expense and
*-- inconvenience, and second the simplified introduction provided by
*-- "Understanding the Jewish Calendar", by Rabbi Nathan Bushwick,
*-- Moznaim Publishing Corporation, Brooklyn, 1989. Any mistakes in
*-- applying the algorithms are entirely mine.
*-- The main function in importance is Roshashana ( sorry for
*-- the spelling, but the number of characters allowed in dBASE cannot
*-- exceed 10 ); I have no means of checking whether or not it works
*-- properly for periods outside the period 1900-2100.
*-- If you try to create a calendar, you will find that using
*-- these functions repeatedly is very slow because they are set up to
*-- recalculate Rosh Hashanah from scratch on each call. This is
*-- required by passing only the year as a parameter and returning only
*-- a date; you can easily adapt them so the date, hour and chalokim
*-- of each Molad Tishri and date of each Rosh Hashanah are saved in
*-- public variables between calls and made available to later calculations.
*-- Note also that given the date and time of one Molad Tishri,
*-- finding the next or previous one requires only adding or subtracting
*-- 12 or 13 times the length of a lunar month. Then, applying the
*-- dechiyoth to the date and time of the Molad Tishri will find Rosh
*-- Hashanah, and the dates of it and its predecessor can be used to find
*-- the kebiah. Given the kebiah and the date of Rosh Hashanah, the
*-- entire calendar is known and can be constructed from code like that
*-- in the latter part of the Dat2Heb() function.
*-- If using these functions for purposes such as figuring out
*-- when a boy is bar mitzvah, please remember some details: a child born
*-- after sundown has a Hebrew birthday matching the next civil day,
*-- anniversaries of events occurring in Adar follow special rules, and
*-- many congregations postpone the celebration if the birthday falls
*-- on the Sabbath or if the celebration would fall on certain major
*-- Sabbaths. In addition, see the notes to the Civildate() function
*-- about Heshvan and Kislev 30, particularly in connection with
*-- Yahrzeit, determining the anniversary of a death.
*-- I don't know Hebrew or Yiddish; my sources use different
*-- transliterations of words and I have in some cases used one form,
*-- in others another. If my spelling, or use of words such as "Hebrew"
*-- that have on too many occasions been used as epithets, gives offense,
*-- I apologize. Suggest more neutral terms that still convey what it
*-- is these functions do if you can; I look forward to hearing from
*-- you. Until then, please believe that I approached this from a
*-- sense of awe at a calendar so accurate and so old, and in a spirit
*-- perhaps akin to that quoted by Rabbi Bushwick from the Gemara,
*-- Shabbos 75b, "Anyone who has the ability to calculate the motions
*-- of the heavenly bodies and does not do so is refusing to see the
*-- greatness of God's work."
*-- Jay Parsons
*-- Bernardsville, NJ
*-- March 27, 1993 ( Nisan 5, 5753 )
*--
*-------------------------------------------------------------------------------