New Moon- When calculations count.

New Moon- When calculations count.

Yoel Halevi One comments

New Moon April 2022

I have been contemplating the question I raised in regards to when this new lunar month has started. I will admit that it kept me up last night and it took me a lot of time to make certain decisions. In truth, because I am just an individual who has expertise in the field, anything I say is only a suggestion and should be always taken with an advisory. 

I reached out to several world-renowned experts on ancient calendars to seek any information on issues of obstructed vision during a new moon sighting. The information which was provided showed serval clear ideas:

1. A month in the lunar-solar calendars was ideally 30 days long. This was a system that was adopted from eastern math which saw 60 as a perfect number. However, they also knew a cycle was not always 30 days and had to confirm how many days had actually passed since the last sighting.

2. In Babylon math was part of the system which allowed the experts to determine when the next new moon should be. This math was advanced and could predict things in a relatively accurate fashion. 

3. When clouds obstructed the horizon messengers were sent to other locations to check if others might have sighted the moon. If not, a 30-day month was used. However, they would first send out messengers to other locations to check if any other cities were able to sight. In any case when there was no answer the central power (King and Temple) would make a decision based on what they knew. 

4. In case of things were wrong there was a retroactive correction of the month which was done by officials under the orders of the king. 

Most of these principles were implemented in the Jewish Lunar-Solar calendar in the 2nd temple. The Jewish Lunar-Solar calendar is the calendar that was and is used by most Jews to this very day. However, the use of calculations was introduced because of the difficulty to send the information from the land to the diaspora. The calculation in time became corrupted due to the lack of adjusting it to the changes which happen with the movement of the earth and the moon. 

The introduction of calculations also led different groups to a decision that the Lunar-Solar calendar was incorrect and the creation of several other calendars described in the book of Jubilees (circa 100BC) and calendar scrolls such as 4Q317. 

The principles used by moon sighters today are the same as were used by rabbinic Jews till the crusades which destroyed the Jews community in Israel which continued to sight the moon till the 11th century. From that point, only calculations were used due to the lack of Jewish witnesses from the land. 

The renewal of sightings was started over 30 years ago by a group of orthodox Jews who decided to study the subject for theoretical information to maybe be used one day when the original system would be reintroduced into the Jewish world. This gathering of data has created a huge database of what can be expected with the moon cycles. This data has not only shown that we can predict when the moon will be sighted but also that the prediction can also be incorrect. In time Karaites who were also interested in the lunar sightings joined this practice after several centuries of using calculations as well. Nowadays many people around the world use the local moon sightings from Israel to determine when to keep the biblical feasts. This is an astonishing thing to witness, especially when you are one of the people who publish information on the subject.

I think that with the accumulated information on moon sightings and the math we have on the subject it stands to reason that the new moon day would have been after Shabbat, April 2nd, and not the day after. This is a conclusion based on the fact that the conjunction was on Friday evening at 17:15:03 before sunset. The moon the next day was at 2% at sunset (19:00) with more than 24hr after conjunction and with a lag time of 75min. The sky turned dark well before the moon setting and was over the horizon for an extended period of time. In these conditions, based on past observations, the moon would have been visible for a short window. 

I find it important to note that defaulting to 30 days is a completely rational thing and is the normal course of things. My questions resulted from the fact that we had a default last month and that the basic data used (by karaites as well) showed a high potential of sighting. The moon was also not sighted the next day and no report came in. When defaulting in an important month like this one I think it’s important to confirm the moon. Sunday night was also hazy which casts doubt on Sunday night being the right day. 

Hence even when people default it is based on a calculation assumption and not on an actual sighting. The moon was visible on (Monday April 4th) evening and was clearly on it’s third day of renewal (I sighted it from Haifa University at 7:32 PM). On Shabbat (April 9th) the moon was at it’s first half stage making it clear that 7 days ago it was renewed. Ignoring such data is ignoring facts and is not a calculation but real observation. 

This reality has made it crucial to sight the next new moon. If my suggestion is correct then when ever we sight the new moon next month will not be an issue. However, if the moon is sighted 29 days from after Shabbat (my suggestion), then the Sunday night (default) will be on day 28. This is not ideal situation but can happen when dealing with actual sighting. As a result if this scenario happens there will be a need to retroactively adjust the calendar. If the moon is sighted after 29 days for the default then both opinions can be seen as possible. Based on the calculation data the next new moon should be on May 2nd, the moon should be at around 3%. This date places my opinion at 30 days and the default at 29 days. This means that there is no way of knowing what the real day was unless we concider the calculation and observations I have proposed. 

Though I have been doing this for a long time it is not in my power or authority to tell people what to do. This is why I have not answered the question of what I plan to do. What I do is irrelevant to the question because I live in a Jewish community. My way of avoiding any issues with the Torah is to just keep extra days by not doing work and not eating leaven. However, this is just a personal decision that is part of my personal life as a Jew in a Jewish community. I see my community as my living and breathing form of Torah-living and cannot step away from real life because I have an opinion about something. In the past when I was younger it was easy for me to be more militant, but with age and knowledge, I stepped away from this mindset. I decided to use logic and have gone through years of study and obtained degrees in different fields to increase my knowledge. This led me to a study I did under one of my professors which taught me that even in the Tanakh we find that unity trumps opinions and circumstances can affect decision making. This of course does not allow us to violate Torah, but it did show me that there are issues one can be flexible with as long as one is still within the larger picture of the rule. 

These are some more points to consider when discussing the sighted moon calendar.

With prayer for better understanding and a return to a more perfect keeping of the Torah. 

Blessings to all.

One comments

Ana Lopes

July 12, 2022 at 1:46 pm

Thank you for all your efforts, Yoel!

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