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Since the first publication of this booklet in 1979, Stewarton Bible School (SBS) has received many queries about the sacred calendar. In Part Two some of the most frequently asked questions are answered. The Appendices contain information as to how the sacred calendar is set up. New moon times and the beginings of months are given at Appendix A. They should be carefully preserved, because they will keep you informed as to the appointed festival days and seasons when in some future year SIGNS in the sun, moon and stars are scheduled to occur. Stewarton Bible School does not - indeed it cannot - predict the date of Jesus Christ's return. No one knows that date except our heavenly Father (Matt.24:36). What we do say, however, is that when those celestial signs are seen by all the world on a sacred season, day or year, then a vitally important phase of human history will have begun and you need to be aware of that fact. SBS offers this work to the reader with much prayer, trusting that he/she will greatly benefit as a result of its study. Now to those questions and answers.


When does a month begin in the Sacred Calendar? Does it begin on the day of the astronomical new moon (conjunction), or when the new moon is first sighted with the naked eye?


A month in the sacred calendar begins with a first sighting of the new moon. An 'astronomical new moon' (conjunction) occurs when the sun and moon are in a straight line with the centre of the earth. The new moon is not visible to the naked eye at this time; but becomes visible between about 15 and 48 (or more) hours later. In ancient days months began when the new moon was first seen with the naked eye. The ancients literally 'looked out' for the new moon and when it was seen they pronounced the start of the new month. They didn't publish the calendar several months or years in advance as we do today; but started each month when they actually saw the new moon. That is the original and best way to determine the beginning of a month. It completely eliminates the one day discrepancies that even the most conscientiously produced pre-printed calendars are liable to contain.

When, however, astronomers began to calculate the circuit of the moon around the earth, conjunction times became available and calendars based on these times began to be produced, months or even years in advance. The question is: What should we do, now that conjunction times and phases of the moon charts have become available? Do we use computer produced calculations and print a calendar in advance or not? Our answer is as follows. Some Christian groups - including SBS - publish calendars in advance by using mathematical calculations of some sort. However, because the ancient method was to lookout for the new moon each month, we in SBS use computer calculations but also allow a certain period of time for the new moon to become visible, before determining the start of each month. This means that after we have made an allowance for a first sighting with the naked eye, the pre-printed calendar SBS publishes is very much in line with the sacred calendar used in ancient Israel. In 1978 we asked a group of believers in Jerusalem to confirm our findings by actually checking the calendar SBS published against first sightings of the new crescent moon. After looking out for the new moon for several months Elder Charles Dugger of the Jerusalem Church of God wrote this:

"We find that the moon really is new over Jerusalem each month by your calendar and is off as much as two days by the Jewish calendar. Therefore we wish to publish the truth - and we simply need a list of the moonrise after conjunction at Jerusalem. Brother Loughran just list them so that we can take the list straight to the printers."

First Visibility

The next question is: How long after a conjunction does the new born crescent become visible? The answer is: It is not possible to infallibly predict the exact date and time of the first sighting of a new moon. Various factors such as atmospheric pressure, temperature, humidity along the light path, altitude, latitude/longitude, fog, cloud/dust cover, glare etc. can all affect a first sighting. That is the reason why in the calendar and festival charts SBS publishes we use the words: "a likely first sighting should occur," because no one can infallibly predict the moment when the new moon will become visible to the naked eye. The general consensus of authoritative opinion is that a first sighting of the new moon could occur any time between about 15 and 48 hours after a conjunction. I quote two world famous authorities on this matter:


"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 perigree). 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."

You will see from these two quotations that the shortest time lapse for a possible first sighting is 'somewhat less than 15 hours,' and the longest to 'more than 48 hours. ' How then does SBS set out a calendar when it is not possible to infallibly forecast a first sighting? Our answer is: SBS allows at least 24 hours for 'a likely evening (or morning) first sighting' of the new moon to occur before it begins a month. The method we use is explained in the answer to Question 8 and examples are found at Appendix A.

Note: The reader should remember, however, that pre-printed calendars based on calculations were not used by the ancient Israelites. They literally looked out for the new moon each month and then counted to the feasts. This is still the best method.

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Author: David B Loughran
Stewarton Bible School, Stewarton, Scotland
Updated: August 1998