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When does the Hebrew Month begin?

This article is about how we at The Refiner's Fire, determine the 1st day of the new Hebrew month. We very strongly believe that declaring the first day of the month by the "sighted moon" is a long-held myth (not discussed in this article), and we do not advocate that method because it is demonstrably incorrect.

The new month, as we will show, begins in the first full day after conjunction of the moon with the sun, and though many argue "you can't see conjunction", we will show that "seeing" conjunction is irrelevant. One simply does not need to know when the conjunction happened to know that is has happened - by observation alone!

Also, many will argue that a "sign" must be "visible" and since "conjunction" can't be "seen", conjunction can't be a sign! They argue that Genesis 1:14 declares this! We will show that it does not....

All that is required to show that the "sighted moon" is a myth is to WATCH the moon through the entire month, month after month, year after year, to realize one cannot escape the conclusion that the "sighted moon" beginning of the month is terribly erred!

Just as the day ends and begins in darkness (at sunset) and the year can end and begin in darkness1 - so it would follow that the month should end and begin in darkness and not by a "sighted moon".

The astute reader will note a curious lack of scripture citation in this article! That's because there are no scriptures telling us how to determine the beginning of a new month! None! Just as there are no scriptures telling us how to determine the new year, or the day! Do not believe it if someone says "Scripture tells us the month begins at the sighted moon"!

Many will argue scripture specifies the crescent, but that myth has been around so long, it is simply "assumed" to be true! In fact, I dare anyone to find a single scripture saying the new month is determined by a "sighted moon"! Many say it is "obvious" that the sighted moon determines a new month because "anyone" can see the new moon and tell it is a new month! Really? To me, when we see a new crescent, it is instead rather "obvious" that the moon is already a day (or more) old!

Many will argue that it is a matter of historical record that "two witnesses" came forward to declare they had spotted the moon and the new month was declared. Historical record or not, written in Talmud or not, that only adds to the myth that this was the method of determining the new month, it is not "proof".

"Proof", in fact, is simply in the looking - the same way the ancients did eons ago, which, for some reason, we've forgotten how to do! The method of the "sighted moon" is this: It is wrong! Anyone, in Biblical times as well as today, by simply observing the moon throughout the month, month after month, year after year, one would inescapably draw that conclusion. Just watch the moon!

Observing the Moon

The proper technique is to take advantage of all the signs! We'll discuss the signs in a moment. But first, let's look at some of the problems with the "sighted moon".

The error of the "sighted moon"

While those who insist the new month begins at the sighting of the new crescent moon, it is, in actuality, without foundation because if the sighting of the new crescent means that that sunset becomes the 1st day of the month, then it also means the sighting of the LAST crescent of the current (old) month (seen at sunrise) would necessarily mean that the following sunset would be the last day of the current month. After all, at the next sunrise, when no crescent is seen, you must be in the last day of the month if "seeing a new crescent" means the month is just beginning!

You really must apply the same rule! If sighting the "new crescent" means that that sunset marks the "1st of the month", then sighting the "last crescent" of the old month must mark the last day of the current month! But that would mean that the following sunset, that is, the 2nd sunset after the last "old" crescent was spotted, would have to be the 1st day of the month, but alas, no new crescent is visible that soon, so the theory that the new month begins by the sighted crescent is busted by this simple, elementary observation.

Some will argue, while defending the "sighted moon" new month, that scripture defends the method. They will cite Genesis 1:14 arguing that the word for "sign", which in Hebrew is "owt", insisting that it implies the sign must be "visible". Thus by demanding "owt" means "visible sign", they conclude and insist that the month can't begin by conjunction because a moon in conjunction can't be seen, thus can not be a "sign". But this is a dreadful twisting of scripture and a very poor conclusion.

Genesis 1:14 says "Let there be lights in the dome of the sky to divide the day from the night; let them be for signs, seasons, days and years". We see no one arguing that the "year" is determined by a "visible" sign! Yet no one can "see" the sun pass by the same spot in space that it passed 365.2422 days earlier, but we can still determine a new year has begun! And the day itself begins when the sun has set! The sun has disappeared! It's NOT visible! You can no longer "see it", yet the absence of the sun tells you a new day has begun.

But we don't have anyone saying that can't be a "sign" because you can't see the sun! So why do they insist that the absence of a visible moon can't be a sign? They insist, apparently, because they simply have not thought about the problem and are desperate to "prove" the long-held myth that "this is the way the ancients did it".

So some will argue that Genesis 1:14 says only "light" is a sign! Really? Do we find that scripture actually says that only the "light" of the moon is the "sign"? Can you say that with a straight face? Then why does Genesis 1:14 say " divide the day from the night", that is, night, i.e., darkness, itself is that not also a "sign"? And why would YHWH use "darkness" as one of the plagues of the exodus (Exodus 10:21-22) if it were not a "sign"?! Come on! Things unseen are as much a "sign" as things seen2!

Then there is the problem of the age of the new crescent moon. To be visible, the moon must be far enough away from the sun and high enough in the dusk sky to present a visible crescent which is bright enough to be seen in the bright glow of sunset! (But if the moon is far enough away from the sun to be seen, does that not automatically mean it is already older than "new"? That fact alone should be sufficient to tell the observer that upon sighting a crescent, it only indicates that the month began already! But I digress.)

Since the moon orbits the earth in an ellipse, with a close point (perigee), and a far point (apogee) from the earth, and the orbit itself precesses around the earth, and the moon speeds up or slows down in its orbit depending on whether it is near perigee or apogee, that means that each and every month, the moon "presents" itself to us as a new crescent at a very different "age"! That is to say, sometimes, even though the moon is actually there, in the sky at at sunset, it is still too close to the sun to be seen at that sunset, and one must wait another FULL DAY before it can be sighted! That automatically means your method of determining the day of the new month is extremely flawed! You can't reliably "sight" the new moon at the same lunar "age" each month!

Some months in fact, from the geographical latitude of the Holy Land, you can see the new crescent when the moon is only about 1 day old, such as in the Spring, when the moon is both high enough and far enough from the sun, while some months you can't spot it till it is over 2 days old, such as in the Fall when the moon is certainly far enough from the sun but is not high enough in the sky to be spotted! Would YHWH really want us to use such an unreliable method?

Still another problem! Since the month is defined by the new moon, that simple fact necessitates the "middle" of the month being defined by a full moon. After all, if the moon is "new" when it is between the earth and the sun3, then it is "full" when the moon is on the other side, that is, the earth is between the moon and the sun, and "full" MUST mean the month is half over! Simple. Obvious. And you really can't get around it! When the moon rises full or nearly full, your calendar should say it has become the 15th of the month! (The average lunar month is 29.5 days, so 1/2 a month means the 15th day must begin when the moon is full or becoming full.)

But the "sighted moon" month has a serious detrimental side-effect! That side-effect is that if one has declared the new month only by the sighted moon, it means that when the middle of the month comes around, when the calendar says it's the 15th, the moon simply does not rise with the setting sun on the 15th, rather it rises much later after sunset! Hours late! Too late to be the middle of the month! Oops! Something is wrong! What is wrong is you chose the incorrect day to call the first day of the month! Indeed, if you are watching for the moon on the day it does rise at or near sunset, when it will rise full or nearly full, your "sighted crescent" calendar says the date is only now becoming the 13th or 14th! By this simple observation, you can see, indeed prove, the "sighted moon" new month is wrong!

Using all the signs

The solution is to use all the signs as they would have in ancient days before computers. What follows is a list of these signs and how they are used:

  1. Watch for the old moon
  2. Watch for "1st Quarter"
  3. Watch for the approach to full moon
  4. Watch when the full moon rises
  5. Watch for when the full moon sets
  6. Watch for "3rd Quarter"
  7. Keep a record of the instances of 29 and 30 day months

Admit it! You don't do these 7 things, any of them, and no one you know does these things! Today we don't need to! But in ancient times, before the computer, these were the items they would have carefully watched and tracked!

The "old moon" is a critical observation. The old moon tells you how long till conjunction and hence, how long till you will see the new crescent moon. Many people today, accepting of the idea of "sighting the new crescent" simply have no idea the "old crescent" is also visible. One must be up before sunrise to see the old crescent. That's a problem for us, but not for the ancient Levites who were assigned the responsibility! They would watch the old moon, and record its appearance, angle of its "horns", and height above the horizon, month after month, year after year, and they would compare those observations with when the "new" crescent was seen, and build a knowledge of just when the conjunction was! They did not need to "see" conjunction to bound when it happened!

1st Quarter4 tells you a lot! 1st Quarter is when the moon is 1/4 the way through its orbit, and it looks exactly half way to a full moon. Almost no one realizes it, but a 1st Quarter moon rises around local noon, and sets at midnight. Thus, as the visible terminator of the moon is "concave" before 1st quarter, and "convex" after 1st Quarter, when you see the "straight line" of the terminator indicating time of 1st Quarter and where it is in your sky tells you a lot about the age of the month, how long till Full Moon, and the length of the month!

Approach to full moon. Similarly, the appearance of the moon after 1st Quarter becomes more and more gibbous. Ultimately, just before the sun sets one night, you will see the moon rise - not yet full - indicating it is not yet the 15th! If you have begun your calendar correctly, the rising gibbous moon will "reveal" evidence if your date is correct!

Full moon rising. Ideally, the moon is perfectly full when it rises exactly as the sun sets. This discussion must be simplified, but, from your location, the moon might not yet be full at sunset, or may rise after sunset having already been "full". (It is possible for the moon to rise after sunset, yet also not yet be full. Skilled observers understand and comprehend these observational issues). Nevertheless, the moon should rise near the time of sunset, and become full sometime through the evening as your calendar says it is the middle of the month. So watching the full/nearly full moon rise time is a very important clue, which tells you that your calendar should be turning to the 15th.

The setting "full" moon. Almost unknown to the world at large is the appearance of the full moon before sunrise and what it reveals about its age! If the moon has already gone through "full" then it will set after sunrise! If it sets before sunrise, then is likely has not yet been "full". It's an important clue, and the skilled observer knows this! (Again, I've had to over simplify, because there are times when the moon will be just setting at sunrise, yet it is not yet full. The point is the skilled observer will be aware of these conditions.)

Watch for 3rd Quarter. Similar to 1st Quarter, 3rd Quarter is a visible and noteworthy stage. A 3rd Quarter moon rises at midnight, and sets at noon. So just where the moon is in your sky when you see the "straight" terminator of the 3rd Quarter moon is a clue to how old it is and how many days are left in the month.

Keep a record of months. The average lunation is 29.5 days. This means that "months" must alternate between 29 and 30 days. But since several months in a row can exceed 29.5 days, it means that sometimes successive months must be 30 days! In fact, this can happen up to 4 months in a row! (Similarly, it is possible for two consecutive months to be 29 days!) So a record of the observations of the moon, and a record of the days of the preceding months, is very helpful in assessing if the upcoming month will be a 29 or 30 day month.

What does this all mean? It means simply this: By observing the moon throughout the entire month and not by the "sighted" new moon alone, the skilled observer assigned the task knows exactly the period when the moon is passing through conjunction, even though conjunction itself is not and cannot be seen and thus, which coming evening will be the 1st day of the new month. No crescent "sighting" is necessary. Indeed, with this knowledge, upon sighting the crescent, you realize that the first crescent is only a sign that the month has already begun!

Achieving the same by modern techniques

In our time we don't have to watch the moon all month year after year! Today we are blessed with the ability to compute the time of lunar conjunction. We can use that to our advantage! It turns out there is a 100% correlation with observation if you do the following:

Why this works: Conjunction, that time when the moon is closest to the plane between the earth and the sun, necessarily must happen on the last day of the Hebrew month for the next sunset to become the 1st day of the new month. Also, the 1st whole day of the new month must be just after conjunction, or the calendar will not indicate the half-way point of the month on the proper day when the moon is becoming full! Since a month must have either 29 or 30 whole days, assessing the time of conjunction from sunset - the demark for a Hebrew Day - makes perfect sense. If conjunction happens "in" the current day, i.e., before sunset, then the old month is ending. If conjunction happens "in" the period after sunset, then it happened in what must be the 30th day.

This method exactly duplicates the method of observation! By observing the moon throughout the month, even though the moment of conjunction remains "unseen", the observables (described simplistically above) provide the same assessment of whether or not the current month needs a 30th day. The advantage of the "modern" method is that one does not need a "team" of skilled observers to record endless years of data. Modern knowledge of astronomical computation provides a quick and accurate answer.

There is the potential (though exceedingly rare) that there might be a month when the moon is in conjunction at the same moment as sunset in Jerusalem. What does one do then? Is the conjunction counted in the current day or the next? By observation, realize they would not have had any idea that conjunction was simultaneous with sunset, so what would they have done by observation alone? And what "rule" should we apply to our modern computation?

By observational techniques alone, this is where the "old" moon plays a critical role. Remember, the "moment" of conjunction is not and cannot be known by observation. But the appearance of the very old crescent of the current month - the "thickness" of the crescent, its position above the horizon, the "tilt" of the horns - all reveal to the experienced observer the length of time before the moon will be in conjunction. By experience, seeing a very "thick" crescent yet knowing the moon will not be visible the next morning (again by experience), means conjunction is quite far off, i.e., over one day. So though they don't know the exact time of conjunction and they don't know that that particular conjunction will be at the same time as the sunset, they do have a very good idea that the conjunction will be late the next day! How can I say this? It's very easy.

If the appearance of the "thick" crescent is saying that conjunction is OVER 24 hours away, then they know conjunction is "in" the next day, well after sunrise - and not in the current day. They would assess that the next day would be the last day of the month. Therefore, by observation, a conjunction which is exactly at sunset, presents the same conditions as a conjunction that they already know would know would be "late the next day" and thus the call is easy. Conjunction is "in" the NEXT day, so the following day after that is the 1st day!

And they would be right! Why? Because even they know, that even though they can't see a conjunction at sunset - they can say to themselves: "If conjunction is at the same moment as sunset, then the following sunset, the moon is decidedly, clearly, 1-day old, and the day just ending must have been the 1st day of the month."

So our "rule", by modern computation is simply this: A conjunction exactly at sunset falls to the preceding day. Thus, we apply the same logic as by observation, and the sunset of the conjunction signals the beginning of the 1st day of the new month.

Now you know the "rules" for the calendar we advocate at The Refiner's Fire. If conjunction is before (or exactly at sunset) in Jerusalem, that sunset becomes the 1st day of the month. If conjunction is after sunset in Jerusalem, then the current month requires a 30th day.


1"Adar", the last month of the Hebrew year, originates from an ancient Canaanite meaning: "to be dark". See

2Please understand this statement. Things "unseen" which would otherwise be observed from the Holy Land are not the same thing as, for example, a total lunar eclipse which, if not visible from Israel, is the same as "it did not happen". Even though a total lunar eclipse was known to have happened and was visible somewhere in the world, if it was not witnessed from Israel, it cannot have any significance, as to ancient observers in the Land, if an event happened, but it was not possible to have been observed from the Land, as far as they were concerned, it did not happen! A phase of the moon is quite different. Conjunction is understood no matter where in the world the observer is located.

3Some argue that the "modern" definition of "new moon" is different than the ancient. Baloney! The term "new moon" has always been defined by the moon passing between the earth and the sun as the period in which it is not visible! This is discernible from observation alone! Modern astronomy may define it as the moment when the celestial longitude of the moon and the sun are the same, but the meaning in ancient times was the same! Ancient observers knew full-well that when the moon passed between the earth and the sun, it passed from "old" to "new" at an "unseen" point. Thus, they knew full-well that once the moon was again "visible" it was already PASSED "new". A visible crescent was always nothing more than an indication to the observer that the month had already begun!

4Proponents of the silly "Lunar Sabbath" calendar will argue that "1st Quarter" will always be on a Sabbath. But the folly in their theory is that "1st Quarter" would only happen on the "7th" or "8th" day of the month, every month, only if the moon's orbit was circular. But the moon's orbit is not circular (as can be ascertained by observation)! So by actual observations the day of "1st Quarter" can be early or it can be late, but not "always" on the 7th day of the month. Nevertheless, watching for 1st Quarter, to a skilled observer, is a huge clue about when when the next conjunction can be expected, and whether full moon will be "early" or "late".

5Also not substantiated in this article is the fact that astronomical events, if indicative of anything, must be sanctified from the Holy Land, the seat of YHWH's residence on earth, Jerusalem. We do not, for example, determine if a month has begun by whether or not the moon went into conjunction before or after sunset from Hawaii!

Other articles to consider if you are interested in more on this topic: