Estimating The New Moon For Each Month
Using The Best Available Astronomical
Data From The U.S. Naval Observatory
and H.M. Nautical Office.
Nick Wood
1). New
Moon Conjunctions For Years 2001-2002 (Spring To Spring) In G.M.T. (Greenwich
Mean Time) or Universal Time.
2). Two
Hours Must Be Added To Bring The Conjunction To Jerusalem Time.
3). Another
Twenty Four Hours Must Be Added, Because According To The U.S. Naval
Observatory, The First Visible Crescent
Of The New Moon Cannot Be Seen For
About 24 Hours After The Conjunction, But
Sometimes Slightly Less Or Slightly
More. There Is Now Computer Software
Available Called “MOONCALC”, Which
Can Help In Determining Whether Or Not A
“Possibility Of Sighting” Exists On A
Given Night. It Is Not Simply The Amount
Of Time Which Has Passed Since The
Conjunction, But Other Technical Factors
Such As “Lagtime”, “Altitude”, “Azimuth”
And Time Of Sunset, Which Must Be Taken
Into Account.
Lagtime:
The span of time between Sunset and Moonset.
Altitude: The height of the Moon above the visible horizon.
Azimuth:
The angular distance of the Moon from True North.
4). The New
Moon Is Usually Visible During Dusk (Between Sunset And Total
Darkness) And RARELY A Few Minutes Before
Sunset. In Either Case The “New
Moon” Is Declared The Day Just Beginning.
5). In
Temple Times, According To Alfred Edersheim, “It Was Ruled That A Year
Should Neither Have Less Than Four Nor
More Than Eight Full Months Of Thirty
Days”. (A Lunar Month Can Only Have Either 29 or 30 Days.)
NOTE:
As we grow in grace and knowledge, this knowledge may need refining in
the future, but we are doing the very best we know how, to get back to “The
Faith Once Delivered To The Saints”.
Interestingly,
in some years if both NISAN and IYAR have 29 days, then PENTECOST will be on
SIVAN 7. Alternatively, in some years both NISAN and IYAR may have 30 days, in
which case PENTECOST will be on SIVAN 5.
Unger’s
Bible Dictionary under the article heading “Festivals” – sub-heading
“Pentecost” states: “… the Jews, who during the SECOND TEMPLE kept Pentecost
fifty days after the 16th Nisan, rightly interpreted the injunction
in Lev. 23:15-22. The fiftieth day, according to the Jewish
canons, may fall on the 5th, 6th or 7th of
Sivan…”
The month
of NISAN or ABIB is declared according to the state of the barley crop in the fields
around Jerusalem. If ABIB is not declared then the month is ADAR II.
N.B. These
estimations for Spring 2001 to Spring 2002, are at present based on the working
assumption, that the Barley Harvest in Jerusalem will be ALMOST ready at the
end of March. As this period is AFTER the Spring Equinox, this is a reasonable
working assumption at this time.
We must
remember however, that it is God’s Word which is paramount in determining the
beginning of a New Year, and if the Barley is NOT “ABIB” then a 13th
month must be added to the old year. These estimations are therefore dependent
upon this vital principle.
An
interesting point to note is that the Jewish Calendar, begins Nisan or Abib on
Sunday 25th March 2001 (or in actual fact the evening ending the Sabbath
24th March 2001. As the astronomical conjunction takes place at
around 3.00.a.m. on Sunday morning Jerusalem time, the Jewish Calendar is
actually declaring a New Moon day beginning, EVEN BEFORE the time of
conjunction. This is obviously a nonsensical notion, and another simple “Proof”
of the errors and inaccuracies of the Fixed Mathematical Jewish Calendar.
An easy way
to keep track of the True Calendar throughout the year, is to mark the Hebrew
days onto our standard Roman Calendar. In other words we know that the New Moon
of TEVET was observed the evening of Wednesday 27th December 2000,
so we can mark Thursday 28th December 2000 as TEVET 1. Now mark off
29 days in succession, because we know that a lunar month has either 29 or 30
days. This should bring us up to Thursday 25th January 2001 marked
as TEVET 29. All we now need to do is wait and see if the New Moon is sighted
that evening in which case Friday 26th
January 2001 will be marked as SHEVAT 1. If the New Moon is not sighted until
the following evening then Friday 26th January 2001 will be marked
as TEVET 30 and Sabbath 27th January 2001 will be marked as SHEVAT
1. As we can see there is always an element of uncertainty over the exact
appearing of a New Moon, which should help to train us all to WATCH very
carefully.
Month Days Hours Minutes
MAR-01 25 01 21 Conjunction GMT
plus 02
-----------------------------------------
25 03 21 Conjunction
Jerusalem
plus 24
-----------------------------------------
26 03 21 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 26th March Therefore Estimated
NEW
MOON NISAN à TUESDAY 27th MARCH 2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Nisan à Sunday 25th March 2001]
Month Days Hours Minutes
APR-01 23 15 26 Conjunction GMT
plus 02
-----------------------------------------
23 17 26 Conjunction
Jerusalem
plus 24
-----------------------------------------
24 17 26 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 24th April Therefore Estimated
NEW
MOON IYAR à WEDNESDAY 25th APRIL
2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Iyar à Tuesday 24th April 2001]
Month Days Hours Minutes
MAY-01 23 02 46 Conjunction GMT
plus 02
-----------------------------------------
23 04 46 Conjunction
Jerusalem
plus 24
-----------------------------------------
24 04 46 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 24th May Therefore Estimated
NEW
MOON SIVAN à FRIDAY 25th MAY 2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Sivan à Wednesday 23rd May 2001]
Month Days Hours Minutes
JUN-01 21 11 58 Conjunction GMT
plus 02
-----------------------------------------
21 13 58 Conjunction
Jerusalem
plus 24
-----------------------------------------
22 13 58 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 22nd June Therefore Estimated
NEW
MOON TAMMUZ à SABBATH 23rd JUNE 2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Tammuz à Friday 22nd June 2001]
Month Days Hours Minutes
JUL-01 20 19 44 Conjunction GMT
plus 02
-----------------------------------------
20 21 44 Conjunction
Jerusalem
plus 24
-----------------------------------------
21 21 44 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 21st July Therefore Estimated
NEW
MOON AV à SUNDAY 22nd JULY 2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Av à Sabbath 21st July 2001]
Month Days Hours Minutes
AUG-01 19 02 55 Conjunction GMT
plus 02
-----------------------------------------
19 04 55 Conjunction
Jerusalem
plus 24
-----------------------------------------
20 04 55 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 20th August Therefore
Estimated
NEW
MOON ELUL à TUESDAY 21st AUGUST 2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Elul à Monday 20th August 2001]
Month Days Hours Minutes
SEP-01 17 10 27 Conjunction GMT
plus 02
-----------------------------------------
17 12 27 Conjunction
Jerusalem
plus 24
-----------------------------------------
18 12 27 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 18th September Therefore
Estimated
NEW
MOON TISHRI à WEDNESDAY 19th SEPTEMBER
2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Tishri à Tuesday 18th September
2001]
Month Days Hours Minutes
OCT-01 16 19 23 Conjunction GMT
plus 02
-----------------------------------------
16 21 23 Conjunction
Jerusalem
plus 24
-----------------------------------------
17 21 23 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Possibly Visible Just After Sunset On 17th October Therefore
Estimated
NEW
MOON CHESVAN à THURSDAY 18th OCTOBER
2001
Astronomical Data From MOONCALC Suggests That
The Moon Is Probably Not Visible
Just After Sunset On 17th
October Therefore Revised Estimated
NEW
MOON CHESVAN à FRIDAY 19th OCTOBER 2001
[Jewish
Calendar New Moon Chesvan à Thursday 18th October
2001]
Month Days Hours Minutes
NOV-01 15 06 40 Conjunction GMT
plus 02
-----------------------------------------
15 08 40 Conjunction
Jerusalem
plus 24
-----------------------------------------
16 08 40 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 16th November Therefore
Estimated
NEW
MOON KISLEV à SABBATH 17th NOVEMBER
2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Kislev à Friday 16th November
2001]
Month Days Hours Minutes
DEC-01 14 20 47 Conjunction GMT
plus 02
-----------------------------------------
14 22 47 Conjunction
Jerusalem
plus 24
-----------------------------------------
15 22 47 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 16th December Therefore
Estimated
NEW
MOON TEVET à MONDAY 17th DECEMBER
2001
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Tevet à Sunday 16th December
2001]
Month Days Hours Minutes
JAN-02 13 13 29 Conjunction GMT
plus 02
-----------------------------------------
13 15 29 Conjunction
Jerusalem
plus 24
-----------------------------------------
14 15 29 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Possibly Visible Just After Sunset On 14th January Therefore
Estimated
NEW
MOON SHEVAT à TUESDAY 15th JANUARY
2002
Astronomical Data From MOONCALC Suggests That
The Moon Is Probably Not Visible
Just After Sunset On 14th January Therefore Revised
Estimated
NEW
MOON SHEVAT à WEDNESDAY 16th JANUARY
2002
[Jewish
Calendar New Moon Shevat à Monday 14th January
2002]
Month Days Hours Minutes
FEB-02 12 07 41 Conjunction GMT
plus 02
-----------------------------------------
12 09 41 Conjunction
Jerusalem
plus 24
-----------------------------------------
13 09 41 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 13th February Therefore
Estimated
NEW
MOON ADAR à THURSDAY 14th FEBRUARY
2002
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Adar à Wednesday 13th February
2002]
N.B. The
Following Month Is Either ADAR II
Or NISAN Depending On The State
Of The Barley In The Fields Around
Jerusalem.
Month Days Hours Minutes
MAR-02 14 02 02 Conjunction GMT
plus 02
-----------------------------------------
14 04 02 Conjunction
Jerusalem
plus 24
-----------------------------------------
15 04 02 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Probably Visible Just After Sunset On 15th March Therefore Estimated
NEW
MOON ADAR II OR NISAN à SABBATH 16th MARCH 2002
Astronomical Data From MOONCALC Confirms That
The Moon Should Be Visible
[Jewish
Calendar New Moon Nisan à Thursday 14th March
2002]
Month Days Hours Minutes
APR-02 12 19 21 Conjunction GMT
plus 02
-----------------------------------------
12 21 21 Conjunction
Jerusalem
plus 24
-----------------------------------------
13 21 21 New
Moon Visible Jerusalem
--------------------------------------------------------------------------------------------------------
New Moon
Possibly Visible Just After Sunset On 13th April Therefore Estimated
NEW
MOON NISAN OR IYAR à SUNDAY 14th APRIL 2002
Astronomical Data From MOONCALC Suggests That
The Moon Is Probably Not Visible
Just After Sunset On 13th
April Therefore Revised Estimated
NEW
MOON NISAN OR IYAR à MONDAY 15th APRIL 2002
[Jewish
Calendar New Moon Iyar à Sabbath 13th April 2002]
New Moons in 2001
Below are the expected dates of New Moon visibility from Jerusalem for 2001. The "Date of Expected Sighting" is the date on which the New Moon is expected to be seen at sunset. New Moon Day always begins on the "Date of Visibility" at sunset and continues to the next day at sunset. For example, the New Moon will be visible on Saturday February 24, 2001 at sunset making New Moon Day the evening of February 24 and the day of February 25 (until sunset).
Those dates marked with an asterisk will be difficult observations but visibility may be possible, given good weather conditions. On all the other dates visibility is certain, given good weather conditions:
|
New Moon 2001 (Jerusalem) |
||
|
Date of Expected Sighting |
Illumination (%) |
Lagtime (min.) |
|
Thursday January 25, 2001 * |
1.1 |
49 |
|
Saturday February 24, 2001 |
1.73 |
61 |
|
Monday March 26, 2001 |
2.81 |
81 |
|
Tuesday April 24, 2001 |
1.33 |
52 |
|
Thursday May 24, 2001 |
3.18 |
90 |
|
Friday June 22, 2001 |
2.04 |
68 |
|
Saturday July 21, 2001 |
1.22 |
50 |
|
Monday August 20, 2001 |
3.91 |
78 |
|
Tuesday September 18, 2001 |
2.42 |
62 |
|
Wednesday October 17, 2001 * |
1.07 |
44 |
|
Friday November 16, 2001 |
2.19 |
63 |
|
Sunday December 16, 2001 |
3.25 |
86 |
To find out more about predicting
New Moon visibility see the article at:
http://www.geocities.com/magdi_shamuel/karaite_calendar.html
For our Hebrew readers, a
detailed description of the astronomical considerations for predicting
visibility, as well as instructions on when and how to observe from Israel, is
now available each month at (Hebrew fonts not required):
http://www.geocities.com/magdi_shamuel/moon.html
Determining the Day of Rosh
Hodesh by the Court
for the Establishment of the
Calendar
Magdi Shamuel
Before us stand the
commandments of Hashem our God the keeping of which is a “lamp unto our
feet.” The Council of Hakhamim has
spared no effort in studying and investigating to learn the truth, so that we
can do the will of God. We are required to guide the people, to keep and
fulfill the will of God and not stray after our hearts and our eyes. We will
not follow those who have taken it upon themselves to digress from the words of
God and ignore the correct interpretations of the Karaite Hakhamim of past
generations as expressed in their books.
Establishing the beginning of months (Rosh Hodesh) through sighting the New Moon is an ancient law in Israel. This antiquity of this practice is documented in many early sources, Karaite, as well as Rabbanite. The decree of establishing the Rosh Hodesh on the basis of calculations which are unconnected to the appearance of the moon was enacted by the Rabbanite, Hillel the Elder. The method was guarded as a secret to keep the people from knowing about the change and therefore was called by our brothers the Rabbinites "The Secret of Intercalation" (this is testified to in many Rabbinite works, for example "Magid Harakia"' p.35).
Although our brothers the Rabbinites abandoned the sighting of the new Moon they know it to be the correct law and believe that at some future time they will return to that method and they have even required people to learn how to fulfill this commandment so that they will be prepared to do so when the time comes. At a lecture at a scientists' convention at Ariel in Samaria, Professor Ariel Cohen stated "Since the Hebrew Calendar is in error, why don't we correct it now." In addition, there are those among our brothers the Rabbinites who are awakening to return to the fulfillment of this commandment.
The sanctification of Rosh Hodesh according to sighting the New Moon is one of the main characteristics of Karaite Halakhah. In the prayers we declare "Beginnings of Months according to seeing the moon -- Truth!" and this is among the main principals of faith. In accordance, in the Karaite Ketubah (marriage contract) the bride and groom swear "to keep the appointed times of God which are established according to sighting the New Moon". Some Biblical verses which teach that sighting the New Moon is the correct way to establish the day of Rosh Hodesh are:
A) "Let there be lights in the firmament of heaven . . . and let them be for Signs and for Holidays" (Genesis 1:14, Tanakh) (M'DIM=Holidays, cf. Leviticus 23:4). The "Sign" which is for Holidays is the New Moon (cf. also Jeremiah 10:2).
B) "He appoints the moon for Holidays" (Psalms 104:19, Tanakh)
C) The "Rule" of the moon, as it is written "And the moon and stars to rule the night...”(Psalms 136:9, Tanakh)
D) The New Moon is the "Witness" referred to in the verse "It shall be established for ever as the moon and as a faithful witness in heaven, Selah" (Psalms 89:37, Tanakh)
E) The term "month " referred to in the command "This month will be for you..." (Exodus 12:2, NIV) itself indicates that months should be started according to the New Moon. The Hebrew word "Month" (HoDeSH) is derived from a root which means "new" (HaDaSH) and implies a renewing. A perceivable renewing which exists in nature, and which is hinted at in many Biblical verses, is the renewing of the moon which disappears around the time of "conjunction" and then appears anew one or two days later in the western horizon shortly after sunset.
When prevented from actually observing the New Moon, our Hakharnim used calculations based on the most advanced astronomy of their day, which they considered equivalent to actual sighting. The purpose of these calculations was to determine the conditions and time when it would be possible to see the New Moon, without the interference of random factors (such as clouds) which might block the crescent new moon. They called this phenomenon the "Possibility of Sighting".
When it is impossible to see the crescent new moon under the best whether conditions, that is, when the moon has not reached a stage where it has ever been seen in the past under similar conditions, then we can't say that there is a "Possibility of Sighting". In this situation there is no "renewing of the moon " since to our knowledge humans have never perceived a moon in such a state.
The survival of the People of Israel and its peace are dependent on
keeping the holidays in their correct time.
It is the function and duty of the religious leadership to instruct the people correctly to keep the holidays of God according to the sighting of the moon. To remind us of this, the following Biblical passages which warn the people and leadership not to stray from the way of Hashem, were incorporated into the Rosh Hodesh prayers:
"For the idols have spoken vanity and the diviners have seen a lie. . .My anger was kindled against the shepherds and I punished the goats . . ." (Zechariah 10:2-3, Tanakh).
"For He spoke and it was done; He commanded and it stood fast." (Psalms 33:9, Tanakh).
"Praise Him, sun and moon . . .for he commanded and they were created). . . He has also established them for ever and ever; he has made a decree which shall not pass." (Psalms 148:3-6, Tanakh).
"Thus says the Lord, who gives the sun for a light by day and the ordinances of the moon and of the stars for a light by night). . . If those ordinances depart from before me, says the Lord, then the seed of Israel also shall cease from being a nation before me forever. " (Jeremiah 31:35-36, Tanakh).
Correct sanctification through actual visual sighting does not require an immense amount of astronomical knowledge and brings to the looker peace, as our teacher Aaron "the Younger" wrote in his book "Harnivhar", "Certainly sighting the Moon is not among the difficult commandments, rather it is such a thing that anyone who checks the place where it should appear can fulfill and everyone shall go to his place in peace". The procedure used today by the Court for the establishment of the Calendar to determine the day of Rosh Hodesh.
1) Today, in the religious leadership there is a Court for sanctifying Rosh Hodesh (i.e. determining the date of the beginning of each Month) in accordance with Jewish Law. The process of sanctification requires checking predictions of visibility and learning lessons from actual lunar observations.
2) The astronomical calculations are carried out by experts in the field in order to determine if the moon will reach a stage on the night in question in which it can be seen or not.
3) The Court has at its disposal a variety of sources to check the "Possibility of Sighting" the moon. Crosschecking the results of different sources is used to confirm the data.
4) The Court considers eyewitness accounts of sightings of the crescent New Moon as well as sightings of the crescent "Old Moon" (which appears before sunrise shortly before "conjunction") in order to determine in what astronomical circumstances a New Moon will be visible to the naked eye.
5) The Court for the establishment of the Calendar is open to hear any opinion which it will investigate and seriously consider. The Court will adopt anything which fulfills the Karaite principle of establishing Rosh Hodesh according to the sighting of the New Moon or the "Possibility of Sighting".
Utilizing
Modern Science
In order to determine when the New Moon will be visible we must update ourselves with the latest scientific knowledge. We should not be blind followers of outdated scientific theories which have been proven to be incorrect today. Our forefathers acted in this fashion and rejected any method which did not consistently give them an accurate prediction of the "Possibility of Sighting" (see the Karaite work "Or Halevanah" Chs.7,8,9). The Astronomical knowledge and computerization of data which we have today assist us in knowing with great accuracy the position of the moon and the strength of its illumination at any given moment. These computer programs are more accurate than earlier computer programs which were based on the astronomical knowledge of one or two hundred years ago.
Prepared by Magdi Shamuel on behalf of the Chief Rabbi Eliahu Marzuk.
Approved by the Court for the Establishment of the Calendar (Rabbi Avraham Gaber -- Presiding Judge, Rabbi Moshe Feruz -- Member, and Rabbi Eliahu Dabach -- Member).
Translated from the Hebrew by Nehemia Gordon.
The State
of the Moon Required to Declare
Rosh Hodesh
The following is a continuation of our article "Determining the Day of Rosh Hodesh by the Court for the Establishment of the Calendar" which appeared in the previous issue of our Bulletin and discussed the principles which the Religious Council employs in determining the date of Rosh Hodesh. The present article will discuss the movements of the moon, the appearance of the moon from the earth in its different stages, the seven stages of the moons cycle defined by our sages, and which of these seven stages has religious significance and is used to determine the beginning of the month.
The modern age with its technological advancements has enabled us to better understand the physical world around us than in the past. For example, at some point in the past it was believed that the earth was flat. Still later science discovered that in fact the world was round and that everything in the universe revolves around the earth. Today we know that the Earth turns on its axis, goes around the sun, and is orbited by the moon.
In order to describe the position of the Earth in its orbit around the sun astronomers have chosen an arbitrary starting point in space, namely the Vernal Equinox (the first day of spring, on which the length of the day and the night are equal). Every day the Earth advances along its orbit away from the point of the Vernal Equinox approximately one degree until after a full year it returns to that same point in space. In order to describe the moon's position in relation to the sun and the Earth astronomers refer to the stage when the moon passes between the Earth and the sun. This stage is called "Conjunction " or "Astronomical New Moon" (not to be confused with the "New Moon" referred to in Jewish literature which astronomers sometimes call "Young Crescent Moon"). When the moon passes between the sun and the Earth (Astronomical New Moon) its lit side faces the sun and its dark side faces the Earth, the result being that the Moon is invisible from the Earth. Over the next fifteen days the lit portion of the moon facing the Earth will continually increase until the entire half of the moon is facing the Earth is lit. This state is referred to as Opposition (what is commonly referred to as "Full Moon"). For about two weeks after opposition (Full Moon) the lit portion of the moon facing the Earth continually decreases until it again passes between the Sun and the Earth and is no longer visible from the Earth.
As explained above, the moon is invisible from the Earth at conjunction. The Moon actually.remains invisible for about a day or two (shortly before and after conjunction) until one night shortly after sunset the moon reappears to observers on Earth in the western horizon. The phenomenon just described, which is referred to as "New Moon" ("Young Crescent Moon"), was well known in the ancient world and was called in ancient Hebrew the "Hodesh", a word derived from the root meaning "New" (Hadash). The word Hodesh was later was applied to the period between two new moons, i.e. a lunar month (a similar development happened in English in which the word "Month " was derived from the word "Moon") and the New Moon day was sometimes referred to as Rosh Hodesh.
Phases
of the Moon Seen From the Earth
The cyclical movements of the moon can be described from two reference points, specifically that of the sun at sunset and that of the sun at sunrise. For the first 15 days of the lunar month the moon can be seen at sunset and appears both larger and higher than on each subsequent night at this time. This process continues until on the fourteenth or fifteenth of the lunar month when opposition (Full Moon) takes place. On the day of opposition, the moon will rise at sunset and then set the following morning at sunrise. Over the next two weeks the moon will appear at sunrise, at first the moon will be far from the sun at sunrise but it will move closer to the sun at sunrise each day until it appears in the Eastern horizon shortly before sunrise and then a few minutes later disappears and is invisible from the Earth. Shortly after this last appearance of the moon before sunset (referred to as the "Old Moon") the moon will pass between the Earth and the sun and conjunction will take place once again.
The Seven
Phases of the Moon
In their literature, our sages divided the orbit of the moon into seven stages (in Hebrew "Sheva Datot"). This division is referred to in many works including "Aderet Eliyahu" of Eliyahu Baschyatchi and Or Halevana of Yitzhak ben Shelomo as well as others. The following is a description of each of the seven stages:
A) Conjunction (also called "its being burnt") -- when the moon passes between the Earth and the sun. At this point the side of the moon facing the Earth is unlit and the moon is not visible from the Earth. Conjunction can be detected from earth during a full or partial solar eclipse.
B) "From the time of Separation" (also called "its being saved from the burning") -- after the moon passes the point of conjunction. At this stage the moon remains invisible from the earth.
C) "Appearance of the Moon after sunset" (New Moon) -- This stage is the time that the moon is first visible after conjunction.
D) "Appearance of the moon with the sun before sunset" -- In this stage the moon appears even before sunset and remains visible till moonset.
E) "The filling of its basin " (Full Moon or Opposition) -- In this stage the entire lit portion of the moon faces the Earth. When the moon passes across the plain of the Earth's orbit around the sun (the "Ecliptic") there will be a lunar eclipse because the Earth blocks the light coming from the Sun to the moon.
F) “Appearance of the Old” -- In this stage the moon appears in the East before and after sunrise.
G) "Last Appearance of the Moon" -- In this stage the moon will appear in the east before sunrise but not after and will not appear in the east on subsequent days.
Our teacher, the Hakham Tuvia ben Simha Levi Babovitch (1879-1956) of blessed memory, explained the state of the moon required to declare Rosh Hodesh in his book Rosh Pinah (p. 17); "Today the Karaites go according to the Possibility of Sighting which correlates to actual sightings". In explaining the "possibility of Sighting" Hakham Tuvia writes ". . . they perform the calculation and if it turns out that the moon will be visible in the Horizon after sunset then they sanctify [the New Moon day]". According to Hakham Tuvia the purpose of the calculation is to determine accurately the lunar astronomical information (such as the moon's distance from the sun, its height above the horizon, and its lit portion facing the Earth) in order to know if the moon is above the horizon and visible. Hakham Tuvia continues ". . . but if the calculation indicates that it will be impossible to see the moon with the naked eye because of the minuteness of its light then the previous month is reckoned to be full [30 days long]". Hakham Tuvia was clearly of the opinion that the state of the moon must be such that it is has a sufficient distance from the sun and enough light facing the Earth that it can be seen with the naked eye (and not sophisticated optical aids). Unquestionably, Hakham Tuvia was not satisfied that the moon merely set after sunset. He did not accept a moon which had only a minute amount of light but rather required the light of the moon to be greater than that of the background such that the moon would be visible with the naked eye.
In our opinion, the purpose of the calculations is to describe with the greatest accuracy the variable states of the moon and sun and thus answer the problem dealt with by our sages and Hakham Tuvia, namely when can the moon first be seen after sunset with the naked eye. There is no Halakhic difference between a calculation which is off by one day in determining the time of the holidays established by God and a calculation which is off by two days, since both such calculations are meaningless.
Having clarified the purpose of the calculations as determining the possible time of visibility of the New Moon we will discuss in our next article the criteria and computer programs used to determine this important issue.
Prepared by Magdi Shamuel on behalf of the Chief Rabbi Eliahu Marzuk.
Approved by the Court for the Establishment of the Calendar (Rabbi Avraham Gaber) -- Presiding Judge, Rabbi Moshe Feruz -- Member, and Rabbi Eliahu Dabach -- Member).
Translated by Nehemia Gordon.
In our previous articles we explained the principles the Religious Council uses to establish Rosh Hodesh, the seven phases of the moon defined by our sages including the phase of the moon according to which a decree of sanctification of the New Moon day is made (that is, the phase in which it is first possible to see the light of the moon after sunset with the naked eye). In this article we will discuss the factors which affect identification of the New Moon and the criteria which are used to determine if a "Possibility of Sighting" exists.
In order to identify any celestial body one must check three pieces of information: The astronomical position of the body, the medium between the body and the observer, and the "Discernment Capability" of the observer.
Through astronomy we can find out the position of a celestial body, the time it rises and sets, its distance from the Earth, its distance from the sun, its azimuth (i.e. it angular distance from North), and its height above the horizon as well as other relevant factors.
To determine this astronomical data we utilize internationally renowned computer software and astronomical institutes. Among the institutes and sources we consult are the Astronomical Data Service in Colorado Springs, Colorado (which produces an Astronomical Almanac specially for the Karaite community in Israel), the South African Astronomical Observatory, and the magazine Sky and Telescope. We also use a number of computer programs including Distant Suns produced in California, Astronomical Almanac produced in Greenwich, and Moon Calculator produced by Dr. Monzur Ahmed.
A significant factor is what lies between the celestial body and the place of the observation. There may be topographical obstructions between the body and the observer such as mountains or tall buildings. The are certain permanent obstructions in the atmosphere, such as the filtering of the light passing through the atmosphere, which must be taken into consideration, as well as random obstructions such as clouds, smog, etc.
Discerning a celestial body can be accomplished either through naked eye observation or through an optical aid such as binoculars, a telescope, or even through radar which is used to locate an object with laser. For our purposes we must define which method of sighting is admissible for identifying the New Moon. Our sages taught in their books that sighting of the New Moon must be done with the Naked eye since that was the method used to receive testimonies of New Moon sightings in ancient times (see Rosh Pinah by Hakham Simhah Babovitch p.17). Hakham Yosef Sapak argued in his book Geresh Yerehaim (p.6) that since the night is identified by the appearance of the stars, even if an instrument were invented to see the stars during the day (a technology which exists today), the day would not be called night. Similarly, even if an instrument could sight the moon, while the moon was invisible to the naked eye, the instrument would only have accomplished in locating the moon and such a location bears no halakhic significance.
Another example similar to the situation of the moon is that of a pregnant woman. If we were to determine through an ultrasound that a woman was pregnant with a boy, obviously we would not begin from that point to countdown 8 days till the circumcision. Similarly, the days of the month can not be counted from when the position of the moon is located with a radar but only from when it is seen anew with the naked eye. The laser/radar identification only shows the position of the moon but does not indicate that the moon is visible. It is the visibility to the naked eye that is the essence of the New Moon, without which there is no newness (the moon is visible every day with the laser/radar method).
How are the Criteria for Determining the Visibility of the Moon Established ?
The criteria are established based on actual observations of the moon from which the different factors affecting visibility are determined. The criteria are only considered reliable if they conform to actual observations and if not they are meaningless.
If the moon is above the horizon the factor that determines whether it will be visible or not is the ability of the eye to distinguish the moon given the contrast between the light emanating from the moon and the background light of the horizon. An example of favorable contrast is a piece of white chalk on a blackboard. Obviously the chalk will be easily visible. However, if the white chalk is put up against a white board the chalk will be less easily distinguished and might not even be visible. Similarly, in order for the moon to be visible its light must be greater than the light of the surrounding background. This can be measured in two parameters, namely the "Percentage of Moon's Surface Lit" and the "Moon's Lagtime".
Percentage of the Moon's Surface Lit
This is the span of time between sunset and moonset. There is a correlation between lagtime and height (altitude) of the moon above the horizon and the brightness of the background light of the horizon. The greater the lag time the higher the moon will be at sunset and the weaker the background light will be at moonset. Taking into account the Moon's lagtime and the "Percentage of Moon's Surface Lit" we can determine whether or not a "Possibility of Sighting" exists on a given night and how long after sunset the moon will first be visible. The greater the lagtime the earlier the moon will first be visible. If the lagtime is great enough the moon may first appear before sunset.
Before our ancestors had reliable calculations they used a series of Approximations ("Hakravot") to assist them in determining whether the moon would be visible if there were clouds. There had been an approximation called "Approximation with the Sun" which stated that if the moon is seen on a given day before sunset then it must have been visible the night before. This approximation was rejected by Yitzhak ben Shelomo (Or Halevana ch. 9) who proved that there were instances when the moon would be visible before sunset on one day but not visible at all on the previous night. Similarly the age of the moon can not be determined from the moon's height above the horizon on a given night but only from additional factors such as the season, the speed which the moon moves away from the sun, and the distance of the moon from the earth and from the sun.
Sometimes the moon will be thin when it first appears and sometimes it will be thick. This can be seen in figure 1 which compares Tishrei and Heshvan of 5756 (1995). In both months the moon was at about the same height at sunset and had nearly identical lagtimes. Despite this the moon's surface facing us was 4.58% lit in Tishrei and only 2.69% lit in Heshvan (a significant difference). Similarly, sometimes the moon will be low when it first appears and sometimes it will be high, therefore its height above the horizon can not be used to determine its age. A moon first appearing at a given height above the horizon might be a first day or a three day moon since its height is determined by the angle it rises from day to day above the horizon.
In order to determine the time of Rosh Hodesh the Council of Hakhamim carries out monthly observations and uses the latest technology to get more accurate astronomical data than in the past, as our sages before us did. The determinations of the Court for the Establishment of the Calendar are undoubtedly more accurate than those who rely on outdated calculations and criteria. Therefore, the council of Hakhamim authorizes and approves the calendar which it distributes which is produced in accordance with our Halakhah which requires that the beginning of each month fallout on the day which the New Moon actually appears. We believe that in searching after the truth and correcting our ways the Lord will dwell among us and will guide us in keeping his commandments for our good for all of our days. May the Lord bless us and guard us and bring close the time of our redemption.
Prepared by Magdi Shamuel on behalf of the Chief Rabbi Eliahu Marzuk. Approved by the Court for the Establishment of the Calendar (Rabbi Avraham Gaber -- Presiding Judge, Rabbi Moshe Feruz -- Member, and Rabbi Eliahu Dabach -- Member).
The Hebrew original of these articles was written by Magdi Shamuel of Ashdod, Israel and published in the Karaite News Bulletin ‘Bnei Mikra.’
Translated by Nehemia Gordon in consultation with Magdi Shamuel. Copyright 1998-2000 by Magdo Shamuel, all rights reserved.
The Sighting of the New Moon
Crescent
for the Purpose of Defining
the Start
of a New Month Should Be from inside
the Biblical Boundaries of
Israel
Herb Solinsky
1) Using local visibility from outside Israel
leads to arbitrary decisions and confusion. Suppose the new crescent can be
seen from Fort Worth, but cannot be seen from Dallas which is 30 miles to the
east. Should people in Dallas accept
the testimony of people in Fort Worth for visibility of the new crescent to
start a month? What distance should be the limit for accepting someone else's
testimony? Suppose the only places in the United States from which people can
see the new crescent are over 8000 feet above sea level in the Rocky Mountains.
Should people elsewhere accept their testimony? If no one in the United States
can see the new crescent but some people in southern Mexico can see it should
their testimony be accepted in the United States?
2) Knowing that two priests in ancient Israel
were commanded to blow two silver trumpets on the first day of each month to
officially declare the beginning of the month (Num 10:1-2, 8-10), when the time arrived at which the
Israelites were to keep the three annual festivals in one place (Deut.16:5-6,10-11,13-16; 12:5-21), Israel did not practice "local"
visibility to begin the month and determine the festival dates since, when
gathered together at the festivals they were all together in one place with one
high priest. Thus Israel was united in keeping the festivals on the same days
and beginning the months on the same days which is against local visibility
throughout Israel.
3) In some years local visibility could make the difference between a month being considered as the 13th month for part of the earth and as the first month for the remainder of the earth. This would cause the holy days to be kept one month apart for different parts of the earth in such a year, resulting in confusion. The year 2007 provides an example.
4) The land surface of the earth was once one land mass as is indicated from how a world map shows the land fitting together. In this one land mass, to avoid confusion over where to begin the Sabbath, it is only sensible that the international dateline go through the great body of water that is now the Pacific Ocean. This international dateline should never be changed. Hence a first day of each month should respect this international dateline rather than change it every month with a new curved line of first visibility (with exceptional regions due to high altitude visibility or lack of visibility due to rain). Thus the day of sighting the new crescent from Israel should be the first day of each new month beginning at the international dateline.
5) The biblical focus of attention for world government is on Israel, and specifically Jerusalem (Deut.11:11-12; Ps.132:13-14; Isa.2:3; Micah 4:2).
6) According to Num.10:1-2,8-10 the priesthood is commanded to blow two silver trumpets on the first day of each month. The Levites were commanded to be disbursed in 48 cities throughout the 12 tribes (Num.35:2-8), not all over the world. The priests must observe, or reliable witnesses must inform them where they are, concerning the new crescent (Num.35:30; Deut.17:6; 19:15; Mat.18:16; John 8:17; II Cor.13:1; I Tim 5:19). In concept, even though we do not have the Levitical priesthood functioning today, one must still view matters from the standpoint of the priesthood blowing trumpets ON THE FIRST DAY OF THE MONTH using two silver trumpets, implying their being blown from one central location.
7) The role of the land of Israel must be appreciated in the plan of Scripture. This land is called the inheritance of Israel (Num.26:51-56; Deut.4:21; 31:7) while the resurrection to eternal life is called the inheritance of the saints (I Pet 1:3-6). Entering the land of Israel is called a rest (Deut 12:9; 25:19; Josh 22:4; Ps 95:11; Heb 3:11) which is a type of the rest of the resurrection to eternal life (Heb.4:1,8,11). Among the adults in Israel who left Egypt, only Joshua and Caleb were allowed to receive the inheritance by faith (Num.14:6-9,24,30,38; Heb.4:2) which is a type of the faith of the saints that is needed to receive eternal life. The land promise to Abraham, Isaac, and Jacob (Gen.12:1; 15:7,18; 17:8; 26:1-3; 28:10-15; 35:12; Deut.34:4) was a theme for over 430 years (Ex.12:41; Gal.3:16-17) before the beginning of its literal fulfillment. A stranger could become a full citizen in Israel through fleshy circumcision which made him become like a native of the land (Ex.12:48) which is a type of the circumcision of Christ (Cor.2:11-12). The land was to have a Sabbath rest (Lev.25) which is a type of the Sabbath rest of the saints (Heb.4:4). Finally, according to Deut.11:11-12, the eyes of our Creator are always upon this specific land. From time to time through the history of Israel in this land, the priesthood moved from place to place. The first Passover in the land was kept at Gilgal by all of Israel (Josh.5:10). Soon Shiloh became the political center (Josh.18; I Sam.1:3,24). At first King David reigned from Hebron (II Sam.2:11), but afterward he reigned from Jerusalem (II Sam.5:5). For approximately the first 400 years of Israel's history in the land, the political headquarters was not Jerusalem, but the calendar continued regardless of the political center.
8) There is a biblical principle that in the mouth of
two or three witnesses a matter shall be established (Num.35:30; Deut.17:6; 19:15; Mat.18:16; John 8:17; II Cor.13:1; II Tim.5:19). Does
it make sense that if the weather is rainy at wherever the political center of
Israel happens to be, no citizens of Israel from elsewhere in Israel may appear
as witnesses before the priests for having observed the new crescent? No.
9) If the boundary for ending the sighting point for
visibility of the new crescent does not stop at the land of Israel, where does
it stop? The further to the west one goes, the easier it becomes to see the new
crescent, although higher than about 4000 feet above sea level it gradually
becomes ever easier to see the crescent, and low humidity favors seeing the new
crescent. How far to the west can one
go? The answer is to the international dateline in the Pacific Ocean. If one goes
there, then everyone's attention would be focused on the international dateline
to give the very last look to the most western line before deciding that that
day will not suffice for starting the new month. In other words, some islands
in the Pacific Ocean would get all the attention instead of the land of Israel
or its headquarters, Jerusalem. That would mean that local or worldwide
visibility to determine the new crescent would be redefined to visibility at
some islands in the Pacific Ocean. This makes no sense.
10) Suppose some ancient Israelites went exploring on
a ship to North America. How would they begin a month? Without the internet,
without long distance telephone service, et cetera, they could not contact
(even through intermediaries) the high priest for a knowledge of when each month
began. They would have no choice but to use visibility of the crescent from
wherever they were. If such a ship gave rise to two colonies separated by 100
miles, and if these colonies remained isolated from one another, there would no
doubt be months in which they began a month one day apart. If they kept in
contact with one another, then it is reasonable to think that the colony with
rainy weather would accept the witness of the other colony, so that both would
be in harmony on the start of a month. As we add more colonies it becomes ever
more difficult to hypothesize how one could define local visibility.
11) Anciently, if appropriate technology were
available, the ideal situation implied by Num.10; Isa.2:3 would result in all people everywhere accepting the
word of the high priest, whose responsibility would include questioning witnesses
who came from the Promised Land. Some people imagine that it is "not
fair" to use modern technology to report on such visibility, and instead
we must pretend we only have what people had in the days of ancient Israel. Such pretending should also include
pretending we are with ancient Israel, i.e., in the Promised Land. Certainly in
Israel all were united on the day, following the lead of the high priest; hence
rainy areas accepted testimony from clear weather areas in Israel.
12) The question arises of how to put this into
practice. In today's world we can use the internet to determine whether the new
crescent was seen in modern Israel because sighting reports are available.
13) During the years 1907-1927 the German astronomer
Karl Schoch developed an astronomical table or curve based upon certain angles
of the sun, earth, and moon with respect to one another at the time of sunset,
assuming clear weather, no air pollution, and a reasonably low altitude above
sea level (from today's knowledge we can say, under 3500 feet, which is higher
than Mt. Zion). He observed both with and without binoculars, and correlated
data with the results of others. His curve assumes naked eye observations (no
binoculars, except perhaps for initial location to examine without binoculars).
Above that curve one can expect visibility of the crescent; below that curve,
no visibility. In live practice, there is a narrow band near Karl Schoch's
curve where it is near borderline and uncertain, so that some people with sharp
vision looking at the right spot do see it, and others do not. Before internet
reports of crescent visibility were available, I used a computer program that
utilized Karl Schoch's curve. I still use it and can tell whether it is near
borderline, but it's not known exactly how wide the near borderline condition
should be (roughly plus or minus 1/4 of a degree, but even lower on Schoch's
curve if the humidity is very low or during the autumn when a low crescent
looks like a flattened backwards C in the northern hemisphere). Before such
technology and astronomical theory, one would have been reduced to local
visibility (although this seems to defy any clear definition), perhaps
augmented with selected information about visibility elsewhere.
14) In a covenant with Abraham the southwest border of
the Promised Land is stated in Gen.15:18. There it states (on the southwest) the River of
Egypt. The Pentateuch and Haftotahs, 2nd edition, edited by J. H.
Hertz (London: Soncino Press 1968) comments on this verse that the River of
Egypt is “the Wady-el-Arish, which is the boundary between Egypt and
Palestine.” A map on page 71 of Baker's Concise Bible Atlas by J. Carl Laney
(Grand Rapids: Baker Book House 1988) shows the Wadi el-Arish at the place
where other maps show the Wadi of Egypt or Brook of Egypt that starts at the
Mediterranean Sea and goes toward Eilat (also spelled Elath or Eloth), but
appears to stop in the desert before reaching Eilat.
The TANAKH (Jewish Publication Society) translation of
I Ki.9:26 states, "King Solomon also built a fleet of ships at
Ezion-geber, which is near Eloth on the shore of the Sea of Reeds [Red Sea
which goes into the Gulf of Aqaba] in the land of Edom". Ex.23:31 states, "I will set your
borders from the Sea of Reeds [Red Sea at Elath] to the Sea of Philistia [Mediterranean Sea]. . . "
The NIV Study Bible (Grand Rapids: Zondervan 1985) map
4 shows the region labeled Edom and continuing down through Elath (using a
color marking and an identifying legend) to be part of the Empire of David and
Solomon. (I also have a Topical Reference Edition of the NKJV, Thomas Nelson
Publishers, 1994, with map 4 color coded to show this whole region down to
Elath belonging to Judah.) Because the southern desert down toward Elath was
not populated due to lack of rain and opportunity for crops, most maps ignore
it and even cut off the map before it reaches Elath. The use of Beersheba in II Sam.24:2 in the expression "from Dan to
Beersheba" indicates that Beersheba was the most southern populated city,
not that the territory of the kingdom ended there.
Some years ago when Israel agreed to give back the
Sinai region to Egypt for a peace treaty, I was very surprised until I
investigated and learned that according to Jewish scholars (as summarized in Gen.15:18; Ex.23:31; I Ki.9:26, mentioned above), Israel was only giving Egypt
what Israel considered to be reaching up to the boundary specified in
Scripture. The modern southwest boundary of Israel is believed to be the
boundary stated or directly implied by the three verses.
15) Historical evidence concerning testifying about
having witnessed the new moon does not exist before the Mishnah which dates
from about 200 CE. I do not accept the Mishnah as an appendage to the Torah,
for otherwise one would be hard pressed as to why one should arbitrarily pick
and choose what one wanted to accept from it. Also, Mat.15; 16:11-12 and Mark 7 imply opposition to accepting the Mishnah.
16) Isa.2:3; Micah 4:2 says "the law will go forth from Zion",
but that does not prevent witnesses from traveling to Zion and testifying in Zion.
After testifying, the law goes forth from Zion. Anciently, Israel would often
be forced to keep a second day as the alternative start of the seventh month (I Sam 20) until time passed for witnesses to arrive and
testify, so it would be clear which of the two days began the month. If no one
testifies for the first day and the second day, how long should the priests
wait? Why not wait up to the time of the ninth day of the month to accommodate
the fast day, the tenth day of the seventh month? While it is true that priests
could not go back in time and perform ceremonies over again, they can accept
the testimony of witnesses retroactively and thus avoid artificially limiting
the location of witnesses within Israel. (This is both sensible and consistent
with statements in the Mishnah, and this would be workable in ancient times.)
17) If we today were to propose that only Jerusalem
sighting of the crescent mattered, then since there are people today who report
on sighting on the internet, we would ALWAYS be changing close to the festival
date based on rain or heavy clouds over Jerusalem, even if other areas of
Israel were clear, it was NOT a borderline case, and humidity was not an issue.
This shows that Jerusalem sighting does not make matters easier, but actually
complicates matters because there would be more uncertainty on more occasions
than using visibility throughout Israel which includes desert regions so that
computer predictions would only fail in some rare borderline cases.
18) If we had NO reports of actual sighting from
Israel, then a calculation is the only choice, and the vast majority of
the time (no borderline condition or slightly under borderline where low
humidity is a question) these two will agree. The calculated dates will work
over 90 percent of the time. In fact, from 2001, we have no borderline dates
for the first and seventh months through the year 2010.
19) In ancient Israel where no calculations were
available, there was often uncertainty on the day that began the month until
shortly before the festivals at or near the middle of the month. In the case of
the first day of the seventh month, it is virtually certain that they often
kept two successive days for the festival because of no reports of visibility
on the first of the two possible days for sighting. Today, due to computer
calculations, there is uncertainty under rare circumstances, assuming we accept
visibility from desert regions of Israel where it almost never rains. When
actual witnesses from Israel are available, if we reject their testimony and
only use a computer calculation, it is certainly true that we make matters easy
for ourselves, but then we set ourselves up as an authority that contradicts
the use of human instruments for sighting as originally intended, and who would
lack the humility to grasp such authority to oneself? In this modern age people
often want to be able to plan everything in advance. If we have uncertainty due
to a borderline case in a rare circumstance, we can still plan for two
successive days and have ourselves covered. People can plan an airplane trip
one extra day ahead of time so that either event will work out okay.
20) The principles of Karl Schoch's curve are
explained next, without involving ourselves with mathematics. It is simply that
the CONTRAST between reflected light of the moon and the background sky must be
DIFFERENT enough to perceive the arc of light.
For example, why don't people see the stars during the
day? The stars are MOST CERTAINLY there during the day, but we do NOT see them
BECAUSE the CONTRAST between the light of the stars (NOT NOT NOT their SIZE
which is much much much smaller than the center width of arc of the moon!!!)
and the background sky is not enough. In other words, the sun's light is too
brilliant to see the stars' light. The
most important word here is CONTRAST or DIFFERENCE. That is why a nighttime
bicycle rider is told to wear reflective or brilliant colored clothes. It does
NOT matter whether the rider is fat or thin, but what matters is the CONTRAST
between his clothing and the blackness of night.
The same is true in seeing the light of the moon. Some
computer programs (like YALLOP's criterion) are based upon the apparent width
across the center of the moon (or the percent reflection of the light of the
moon, for example full moon 100 percent reflection).
When the sun sets, and you look at the background sky
to the west, the brilliance of the sky is NOT the same everywhere. The further
you look from where the sun set, the LESS brilliant the background sky at that
point. Also, it is MORE brilliant directly above where the sun set, than the
same distance above, but also some distance to the right or left. It is these
angles AWAY from where the sun set that is an accurate measure of the
BRILLIANCE of the background sky. If the moon is at a place where the
background sky is NOT very brilliant, then AND ONLY THEN, can you see it. Thus
the key is knowing the angles (the curve based on the graph coordinates of two
angles) of where the sun is compared to where the moon is. This gives a measure
of the CONTRAST between the background sky and light from the moon.
SUMMARY: The appropriate angles determine the
CONTRAST. If you take some WIDTH of
moon and put it where the CONTRAST is great, you see it. But if you take the
SAME width of moon and put it where the CONTRAST is small, you do NOT see it.
Hence the WIDTH is NOT the main factor, but instead the CONTRAST. This concept
is very very simple, but the mathematics and astronomy are complex.
I DO NOT USE A PROGRAM THAT PREDICTS VISIBILITY OF THE
CRESCENT!!! Instead I use a program that gives me the accurate angles I want.
Then I use the printed table (or chart) that Karl Schoch determined (which
really makes a curve by connecting the dots, so I often call it Schoch's curve)
to see if the moon is ABOVE the curve or BELOW the curve. ABOVE means visible.
BELOW means NOT visible. But borderline is about 1/4 degree above or below the
curve under NORMAL conditions of height above sea level (under 3500 feet),
humidity (close to 50 percent), and a clear sky.
The key for borderline cases is HUMIDITY. The further
you go BELOW Schoch's curve, the lower the humidity must be to see it, but it
still must be high enough when the CONTRAST is there. For the areas with
extremely low humidity one can go 1/2 a degree below Schoch's curve and still
just barely see it.
Sighting the New Crescent Moon
Dennis Rakestraw
The sighting of a new crescent moon takes place at a different time during a twenty-four hour period for every location on earth. There is a line of demarcation called the International Lunar Date Line (ILDL) which you can read about on this Islamic calendar website http://www.ummah.net/ildl Here are some excerpts from that page:
The subject of crescent visibility has been studied in modern times by Prof. Ilyas in Malaysia who has developed several visibility criteria and the concept of the … ILDL. Ilyas's main criterion depends on the moon's altitude (in degrees) above the horizon at sunset and the moon's angular distance from the sun (relative azimuth) at sunset. If a moon's altitude and relative azimuth are greater than certain threshold values, then the moon is likely to be visible. The ILDL is a curved line on a world map which separates areas (west of the line) where the crescent is likely to be seen at the start of the lunar month from areas (east of the line) where the crescent is unlikely to be seen. The probability of sighting the crescent increases as one travels west of the ILDL and diminishes as one travels east of the ILDL. Unlike the solar date line which has a fixed position, the position of the ILDL moves from month to month.
A computer program called MoonCalc by Dr. Monzur Ahmed was used to search the world for locations which satisfy Ilyas's altitude/relative azimuth criterion at the start of a lunar month. On the basis of this scan, world maps for the start of each lunar month were drawn showing areas where the crescent is likely to be seen first. The different coloured bands represent the age of the moon at sunset on the day of predicted sighting. MoonCalc has many other features and also supports several other crescent sighting criteria.
The Moslems are divided on the subject of new moon crescent sightings as are certain Christian groups that sight the new moon each month. There are Moslems that use a standard sighting made in Saudi Arabia or those that accept the division of the world into three regions: The Americas, Europe/Africa/Asia, and Asia Pacific:

And lastly there are those who accept more tightly defined divisions.
There are links on http://www.ummah.net/ildl that will increase your awareness of why the prediction of sighting of a new-moon sighting makes the long-term projection needed by calendars a difficult task. Criteria used to predict new moon sightings are based mainly on angles separating the sun and the moon as seen from earth. It helps to know these terms when reading charts. Keep in mind that because of atmospheric refraction we still see the sun four minutes after it has actually gone down. That is why daylight is usually about twelve hours and eight minutes at each of the two equinoxes on approximately March 21 and September 21 each year. Altitudes and azimuths ignore this small difference unless the term “apparent” is included. Here are the definitions of these and other angular terms:
Azimuth – The position of the Sun or moon in the sky relative to True north 0°. Degrees of azimuth are calculated clockwise from true north, making true west 270°. This is the direction we are concerned with at Sunset of course, 90° and 180° being the eastern and southern points respectively. I hesitate to use the term compass points, which imply magnetic rather than true north.
Relative Azimuth – This is the difference between the two azimuths of the moon and the sun. The greater the difference at sunset, the more difficult the sighting according to Dr. Ahmed Monzur. The new moon is always visible first close to the equator where relative azimuth is smallest. It then is delayed in a parabolic curve facing west as latitude increases. Another reason for the earlier sighting at the equator is that twilight is always shortest at the equator because it is at that point on earth that the sun is moving perpendicular to the horizon at sunset.
Altitude – This is the angular difference between the Sun or Moon and the horizon, the horizon being at 0° and 90° being directly overhead. Due to the atmospheric effects that keep the Sun visible after sunset the Sun’s altitude is slightly negative at sunset. A sun altitude of –5° is considered ideal for the faint crescent sighting on the 29th or 30th day of the month. This occurs at approximately seventeen minutes after sunset at the equator and 20 to 22 minutes after at Jerusalem depending on the season. This explains why the earliest sighting occurs near the equator.
Relative Altitude – This is the difference between the moon’s altitude and the sun’s in degrees. The greater this figure, the more likely is a sighting on the 29th. A relative altitude of less than 10° at sunset makes for a difficult sighting. Somewhere between 9° and 8° it becomes impossible.
Elongation – This is the absolute angular distance between the sun and the moon. You can picture a right triangle in the sky where the height represents the moon’s altitude and the base is represented by the line on the horizon between the setting sun and moon. The elongation is roughly equivalent to the hypotenuse of this right triangle. It isn’t exactly equivalent because of the curvature of the horizon.
Lagtime – This is the time interval between sunset and moonset and is related to relative altitude. A faint crescent can sometimes be seen at the equator with a lagtime of less than 40 minutes. At 32°N, the latitude of Jerusalem, this figure increases to about 45 minutes.
A sample International Lunar Dateline curve follows with the first crescent sighting near the equator and just north of New Zealand:

Anticipated Holy Day Dates
For Year 2001
1st Day UB April
10 April
8
Omer April
11 April
9
7th Day UB April
16 April
14
Iyar 1 April
25 April
24
Sivan 1 May
25 May
23
Pentecost May
30 May
28
Tammuz 1 June
23 June
22
Av 1 July
22 July
21
Elul 1 August
21 August
20
Tishri 1/Trumpets Sept.19 September 19 September 18
Day of Atonement September
28 September 27
1st Day Tabernacles October 3 October 2
Hoshana Rabbah October
9 October 8
Shemini Atzeret October
10 October 9
Cheshvan 1 October
19*** October
18
Kislev 1 November
17 November
16
Tevet 1 December
17 December
16
Shevat 1 January 16*** January
14
Adar 1 Febrary
14 February
13
NOTES
The next
month after Adar 1, in year 2002, will be either Abib (Nisan) or Adar 2,
depending on the state of the barley harvest near Jerusalem.
*** Note that Cheshvan 1 and Shevat 1 are asterisked, showing that
these projected New Moon sightings are borderline cases and are in doubt. The Mooncalc software indicates the probable
sighting for Cheshvan will be October 19, and Shevat 1 will likely be January
16. But to know for sure, we will have
to wait and see.
Note also
that the Jewish New Moon dates in the fixed calendar are usually off by a day
or two during the year 2000 (5761 Jewish calendar). God is clearly beginning to show us the difference between the
TRUE Biblical Calendar, and the approximated Jewish calendar. Interestingly, many Jewish rabbis and
leaders are beginning to question the Jewish fixed calendar. God is beginning to make a difference
between those who really serve Him, and those who pretend to do so, but remain
in ignorance and in sin.
Note also
that Passover in the year 2001 is two days early in the fixed Jewish calendar;
they begin the month of Nisan on Sunday, whereas the New Moon conjuction
or molad itself does not occur until 3:00 am Sunday morning. Since the Jewish day begins at sunset, this
means they back up and begin the first day of Nisan 9 hours BEFORE the actual
conjunction occurs – and remember, the sighting of the New Moon by the naked
eye CANNOT occur until about TWO DAYS after the conjunction itself! Therefore, the Jews in year 2001 will be
celebrating Passover two days early!
Nick Wood in England
wrote to me, drawing my attention to this fact. He declared, “I
have also verified that Abib 1, according to the Jewish calendar, begins at the
end of the Sabbath at sunset on Saturday, 24th March 2001. The actual astronomical conjuction occurs at
about 3:00 am on Sunday morning Jerusalem time. This means that the fixed Jewish calendar is declaring the New
Moon even BEFORE the time of conjunction.
This is very simple and easily verifiable PROOF that the fixed Jewish
calendar is in error and inaccurate.”
Furthermore, the date
in the Jewish fixed calendar for Pentecost is also two days off this year,
being two days early. The Jewish fall festivals,
including Trumpets, Atonement, and the Feast of Tabernacles, are all one day
early in the year 2001.