Holy Day Calendar and The Visible Crescent?

By Jamie McNab

Part Two of Three Parts: Updated 2017

In Part One we looked at some of the alternative calendars being “marketed” to God’s people today. We saw what the Bible does, and does NOT say, about how to determine the new moons and new years. We looked briefly at church history.

We continue in Part 2 to look at how impractical it would have been for God’s people — especially over the past 2,000 years—to have kept a VISIBLE CRESCENT (which is probably the most popular alternative to the traditional Hebrew calendar).

Part 2 was originally in the form of a letter written to a member of God’s church who wished for additional clarification of the calendar topic. I have retained the letter format in this article.

You've asked in your e-mail if I can let you have proof of God's Holy Day calendar. That's what I call a challenging question!!

There are all sorts of people out there who claim to have “proof” of “their version" of God's calendar. I think the last time I counted, I came to over a A DOZEN DIFFERENT CALENDARS — all claiming to be the original Biblical Holy Day calendar. Some people, like Herbert Solinsky, have spent DECADES studying the calendar — only to have fundamental disagreements with other very sincere “calendar scholars” who have reached an entirely different opinion. It all reminds me somewhat of 2 Tim 3:7, “Ever learning, and never able to come to the knowledge of the truth!”

I am enclosing a copy of an article I wrote for one of the recent Church of God Newsletters (this now appears as Part One of this series). It sets out, as clearly as I can, why we accept the calendar maintained by the Jews.

Despite what some may say, I am firmly of the view that the Bible itself does NOT give adequate information from which to develop a working calendar — and that is a FACT.

Compare the incredible amount of detail given in the Bible about LEPROSY (over 110 verses in Lev 13-14 alone!!), with the almost non-existent and vague references to “new moons” or the “beginning of months.” God could have made it crystal clear in the Scriptures if He had wanted to. He chose not to. Yet I do believe He did leave us a standard — an authority over the calendar — as I hope my earlier paper makes plain.

Probably the main alternative to the calculated new moon of the Jewish calendar is the visible crescent new moon. This point is explained at some length in Part One, where hopefully I show that there is NO SCRIPTURE that demands we base the months on a visible crescent.

It seems to me, however, that even common sense shows that a visible crescent is simply NOT POSSIBLE, or practical, as a means to identify the beginning of a new month. A visible crescent, by definition, has to be VISIBLE — it has to be SEEN. Historians will try to explain how “witnesses” had to appear before the Sanhedrin in ancient times to confirm that they had physically seen the new crescent — at which point, if the witnesses seemed credible, the Jewish leaders would allegedly make the new month “official.”

Well, that might be very convenient for those Jews living in Palestine — but makes life rather tricky for those Jews or other believers living in Egypt, Ethiopia, Russia, Spain, Australia and so on!

Without the benefit of telephones, faxes and e-mail — how are they supposed to know when a new month has begun? Bonfires, and fast horseback riders, have been suggested, but come on — if you are over 2,000 miles away from Jerusalem, you probably wouldn't find out for a week or longer that a crescent moon was seen and that the new month has already begun! It is totally impractical! It couldn't work.

In some parts of the Diaspora, the Jews tried keeping TWO Holy Days at a time, so that at least ONE of them might be right! In fact the custom still exists among the Jews to this day.

Consider also the true believers in Britain back in the first and second centuries. They were surely keeping the Holy Days. How could they know for certain when the crescent moon had appeared over Jerusalem 4,000 miles away?

What about the Church down through the centuries? What about the early Church of God in the USA back in the 1700's? How could they determine when the visible crescent had appeared over Jerusalem? Don't forget, the Jews had long since been driven out of Palestine, so there was in fact nobody there to look for the crescent, anyway! And certainly no way to communicate with people thousands of miles away.

But some will no doubt say that nowadays COMPUTERS allow us to work out the times of the visible crescent. So let's just ignore the “inconvenient” problem of HOW the Church figured God's Holy Days over the past 1,900 years when it didn't have effective access to Jerusalem, and didn't have software on smartphones and lap-tops to work from. Let's revert to the visible crescent, they say, even though IT COULD NOT HAVE WORKED for most of God's people since the time of Christ.

Well — what about the computer calculations of a visible crescent? Are they foolproof? Guaranteed? Can those who want to “observe” a “visible crescent” actually rely on a computer instead ? As far as I can tell, the answer is a big NO!

The sighting of the first thin visible crescent is not just a matter of calculating how much of the moon will be visible, and whether the sky will be dark enough to make it out and so on. The visibility is also affected by such things as temperature and humidity, which vary by the day and hour and cannot be predicted. If you go by the visible crescent, then, to be absolutely sure, you must physically observe it with the human eye (or would God allow binoculars? Once again the Bible is silent!).

Following are two quotes, one from the Royal Greenwich Observatory in England, and one from the US Naval Observatory, which explain the difficulty of any computer providing a perfect calculation of a visible crescent (emphasis added):


"It is NOT POSSIBLE to predict accurately the dates on which the new crescent Moon will first be seen each month since there is no collection of reliable, fully documented, observations that can be used to establish the conditions that must normally be satisfied at the time of first visibility.

The simplest basis for prediction is that the Moon should be more than a certain age (measured from the time of astronomical new moon) at the time of sunset at the place concerned.

It is, however, better to use the true elongation (the angular separation) of the Moon from the sun at this time, rather than the age. The new crescent is not normally visible until the Sun is below the horizon and so it is desirable to take into account the altitude of the Moon during twilight. The chances of seeing the new crescent depend slightly on the distance of the Moon from the earth, being greatest when the Moon is closest (i.e. at perigee). The local conditions, especially the height of the observer above sea level and the character of the surrounding surface, are important, and even when the sky is free from cloud there can be considerable variations in clarity of the atmosphere from day to day.

The visual acuity of the observer is also significant. It must be realised too that there are considerable variations in the astronomical conditions with both longitude and latitude on the earth so that even if the weather conditions were good everywhere, the dates of the first sightings would differ from place to place. Predictions can, therefore, only be valid, for restricted areas. Under ordinary conditions, the first sighting will not occur until the age of the Moon exceeds about 30 hours, but a few reliable reports are known of sightings, under very good conditions, when the age has been only 20 hours or even less. It is unlikely that the new crescent will be visible unless the elongation exceeds 10 degrees and the Moon exceeds 5 degrees when the Sun is 3 degrees. It is interesting to note that the new moon can always be seen 30 days after the previous one and in half the cases it can be seen 29 days after, because the length of the synodic month is 29.53 days...

Since it is clear that ANY PREDICTION of the date of first visibility MUST BE UNCERTAIN, it is necessary to decide whether to prefer an early prediction that could not be substantiated by direct observation if conditions prove to be good, or a late prediction that could be vitiated by an observer on the previous day. The simple rule that this Office recommends is that the age of the Moon should be 30 hours at the time of sunset at the place concerned, but this rule is not so reliable in middle and high latitudes.”


Under optimal conditions the crescent moon can be sighted somewhat less than 15 hours after astronomical New Moon. Usually, however, it is not seen until it is more than 24 hours old. Often it is not seen for more than 48 hours... But despite these advances WE STILL CANNOT PREDICT THE EXACT TIME or geographical location at which the young crescent will first be spotted.”

And so we see that even scientists and astronomers, with the benefit of modern computer technology, are unable to GUARANTEE a predicted visible crescent in any particular location! So HOW would the church members in fifth century Britain, or 18th century America, possibly calculate the exact time of the visible crescent over Jerusalem, MANY THOUSANDS OF MILES away (and of course with no computers anyway)??

They couldn't CALCULATE a visible crescent. They certainly couldn’t SEE it themselves. And in 1850 for instance they couldn’t wait for a telephone call from a friend in Judea, to let them know the crescent had been sighted!

So HOW DID THEY KNOW when to keep Passover and the other Holy Days? Simple —go find the nearest Jew, and ASK HIM what the date is!

God has not left His people at the mercy of numerous disagreeing calendar experts. God’s True Church has always relied on GOD’S FAITHFULNESS. God did not leave us without an accurate calendar for nearly 2,000 years. We've always found it with the Jews.

Let’s be sure to HOLD FAST to what we have been given!