Friday, March 21, 2014

From Nehemia Gordon : Potential and Actual Visibility of the moon
Today at 6:20 AM
Karaite Korner Newsletter #616

WWDD: What Would David Do?

On March 2, 2014 the barley was not Aviv in the Land of Israel. As a result, the Feast of Unleavened Bread (commonly called "Passover") will be in mid-April, on the 15th day of the First Hebrew Month. But when exactly is the 15th Day of the First Hebrew Month in the Biblical calendar this year? This is where things get a little complicated. I have mentioned in the past two systems for beginning the Hebrew month: "Potential Visibility" and "Actual Visibility with 30 Day Maximum". I talked about this years ago in this newsletter:

In a nutshell, Potential Visibility means beginning the Hebrew month when the moon "should be" visible even if it is not sighted due to clouds. This past new moon was a great example of Potential Visibility. The moon SHOULD HAVE BEEN easily visible from Israel on Sunday March 2, 2014. However, there was a thick haze over Israel that night and therefore no one sighted the moon that evening. Based on Potential Visibility, the Thirteenth Hebrew Month began on March 2, even though no one saw it. In contrast, according to Actual Visibility with 30 Day Maximum, the month began on Monday March 3 by default. I should point out that the haze lasted for a few days, so no one saw the moon on March 3 either. Let me summarize the two results:

Thirteenth Hebrew Month
Potential Visibility: March 2, 2014 (no sighting due to haze)
Actual Visibility with 30 Day Maximum: March 3, 2014 (by default)

Potential Visibility has a major limitation, specifically in certain months when it is impossible to predict that a moon will be "easily visible" based on the most advance science. This usually happens once or twice a year, although only rarely does that affect the feast days. In the rare occurrences that "Potential Visibility" encounters a new moon that can't be calculated, it reverts to "Actual Visibility with 30 Day Maximum." For example, the new moon for Yom Teruah in 2012 could not be predicted using even the most advanced calculations known to science. On that occasion, Keith Johnson and I traveled to southern Israel where we sighted the new moon from a mountaintop northwest of Eilat. Had no one sighted the moon that evening, the festival of Yom Teruah would have been the following evening based on both "Potential Visibility" and "Actual Visibility with 30 Day Maximum."

I have personally vacillated between these two systems over the years. "Potential Visibility" has the advantage of convenience. It also resonates to the modern scientific way of thinking. The problem is when I ask myself WWDD: "What Would David Do?" It just so happens the Tanakh records the answer to that question in 1 Samuel, Chapter 20. Back then, the future-king of Israel was afraid of King Saul, who he was convinced wanted him dead. King Saul's son, Jonathan, was David's BFF ("best friend forever," for you old folks). David decided to test King Saul by seeing how he would react to David's absence from a royal feast scheduled to celebrate the New Moon. In this context, the Tanakh records the following conversation between David and Jonathan:

"And David said to Jonathan, 'Indeed tomorrow is the New Moon, and I should not fail to sit with the king to eat. But let me go, that I may hide in the field until the third day at evening.'" 1 Samuel 20:5

When I read this story, I ask myself how David could have known that "tomorrow is the New Moon"? The natural explanation for most people who don't know history is that David used the calculations of the "Jewish Calendar." Those calculations determine the time of the conjunction of the Moon with the Earth and the Sun and they are the basis of the Hillel II calendar established in 359 CE and still used by most Jews today. Unfortunately, that would be an "anachronism." The mathematical values of that calendar were worked out by the Alexandrian Greek astronomer Ptolemy around 150 CE and later adopted by Hillel II around 359 CE. Both Ptolemy and Hillel II postdate David by more than 1,000 years.

As a side-note, Hillel II's calculations do not actually calculate conjunction, but rather "average conjunction," which could be off by as much as 12 hours from the true conjunction. The calculation of true conjunction was way beyond Hillel II's mathematical abilities or astronomical knowledge. For example, this month, Hillel II puts conjunction on March 31, 2014 at 3:53am, but true conjunction according to NASA is March 30 at 8:45pm (Jerusalem time = UT+2). That's an error of 7+ hours! Check the sources for yourself!

Maimonides would later provide a more accurate calculation, which he adopted from the Muslim astronomer al-Batani... but I digress. The bottom line is that David could not have known the timing of the New Moon using a calculation worked out by a Greek astronomer 1,200 years after he was born. And even if David travelled in time and learned that calculation from Hillel II, he still would not know the time of true conjunction.

So how did David know that "tomorrow is the New Moon"? Anyone who observes the new moon for a couple of years will immediately see that every lunar month is either 29 or 30 days long. There is no such thing as a 28-day or 31-day lunar month. If the atmosphere is clear, the new moon will always be visible after either 29 or 30 days. There is no need to project Hillel II's calculations over 1,000 years back into the time of David. All David had to do was know that a lunar month can only be 29 or 30 days. The Hebrew language also clearly reflects this knowledge. A 30-day month is called a "full month" and a 29-day month is called "deficient month." There is no such thing as a 28-day or 31-day month in Hebrew terminology or thought. If the moon were not sighted after the 29th day, David could say with 100% certainty: "tomorrow is the new moon"! There was nothing unusual or extraordinary about this statement. Such a straightforward prediction could be made for about half the months in any given lunar year.

So What Would David Do? David would without doubt follow Actual Visibility with 30 Day Maximum! Obviously Potential Visibility is a product of the 20th Century. No question about it. We could argue that it is really a product of the 9th Century CE with some later fine-tuning. Either way, Potential Visibility could not have been known to King David anymore than he knew about airplanes or telephones.

What does all of this have to do with the timing of Passover this year? First of all, it is impossible even with the most advanced science to predict visibility this month. On March 31, 2014 the moon will have 1.01% illumination and 52 minutes of lagtime (the time between sunset and moonset). This is just enough to say the moon might be visible, but more likely might not be. We simply can't say with any certainty one way or another. So this month, no question about it, "Potential Visibility" must revert to "Actual Visibility with 30 Day Maximum."

Where things get really complicated is that last month no one sighted the new moon on the evening of March 2, when it should have been easily visible. As I mentioned above, there was haze all over Israel on Sunday March 2, 2014 making it impossible to sight the moon. If you follow Potential Visibility, the haze didn't matter; you began the month on March 2 anyway. If you follow "Actual Visibility with 30 Day Maximum," then you began the month on March 3 by default.

Those who accept Potential Visibility, can stop reading. Things are very simple. Well, relatively simple. Using Potential-Visibility-reverting-to-an-Actual-Visibility-with-30-Day-Maximum, here are the possible dates of the upcoming Feast:
If the new moon is sighted on March 31, 2014, the Feast of Unleavened Bread will be Sunset Monday April 14 through Sunset Monday April 21.
If the new moon is not sighted on March 31, 2014, the Feast of Unleavened Bread will be Sunset Tuesday April 15 through Sunset Tuesday April 22.

However... if you ask "What Would David Do?", then you must KEEP READING! Using Actual Visibility with 30 Day Maximum, the Thirteenth Hebrew Month began on March 3, 2014 (remember the haze). If we count 29 days, this month should end on either April 1 or April 2, depending on when the moon is sighted. The moon should be easily visible on April 1, unless there are clouds or haze. Israel gets regular dust storms this time of year, so a natural haze is entirely possible.

In David's time, this would not be complicated at all. They would look at the sky on April 1 and decide when to keep the feast based on what they saw or didn't see. Very simple, unless... witnesses sighted the moon on March 31! Then they would accept that the moon should have been visible on March 2, but was not sighted due to haze. This creates three possible dates for the Feast of Unleavened Bread this coming month:

Actual Visibility with 30 Day Maximum:
If the new moon is sighted on March 31, 2014, the Feast of Unleavened Bread will be Sunset Monday April 14 through Sunset Monday April 21.
If the new moon is sighted on April 1, 2014, the Feast of Unleavened Bread will be Sunset Tuesday April 15 through Sunset Tuesday April 22.
If the new moon is not sighted on March 31 or April 1, 2014, the Feast of Unleavened Bread will be Sunset Wednesday April 16 through Sunset Wednesday April 23.

Three thousand years ago, David would not have known that the moon might be visible on March 31, 2014. However, if witnesses sighted the new moon, he would have accepted their testimony knowing that there had been clouds on March 2. Incidentally, the Rabbinical dates of the Feast of Unleavened Bread this year are sunset April 14 through sunset April 21, based on the Hillel II calculations of 359 CE.

I have personally been following the Biblical calendar based on the sighting of the new moon in Israel since 1990 and am not aware of a previous situation like this. What all this means is that the observation on March 31 is super-important not to mention extremely difficult. Only a careful observation will determine when the Feast of Unleavened Bread will begin and this is true whether you are following Potential Visibility or Actual Visibility with 30 Day Maximum. If we are lazy and don't do our utmost to try and sight the moon on March 31, we might be in for a Heavenly April Fool's joke! It is truly humbling that with all our modern technology and science, we must still rely on the Creator of the universe to let us know His appointed times and holy feasts.

Update: After writing this letter, I read it over several times and prayed about it. I then came to the unequivocal conviction that I must get on an airplane and fly to Israel to try and sight this month's new moon. I called up Keith Johnson on his American cell phone only to discover that he was already in Israel waiting for the new moon sighting. There was my second witness! So on Sunday I am saying "Zàijiàn" to China and embarking on the excruciatingly long journey to Israel. I have stepped out on faith and told my Chinese employer that I am taking an unanticipated 2-week absence. The ticket was purchased earlier today with borrowed funds. Please consider supporting this "New Moon Mission to Israel 2014" through prayer and/or by making a tax-deductible donation to Makor Hebrew Foundation at:
(on the right-hand side of the page where it says "New Moon Mission to Israel 2014")

Nehemia Gordon
The Wandering Jew Packing My Bags in Changsha, China

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