Dr. Hoffman looks for the new moon.

Hamodia spoke to experts who are working on the problem

By Yehuda Marks

On Shabbos, we will be reading Parashas Hachodesh, which discusses the mitzvah of kiddush hachodesh - sanctifying the new month.

This is the first mitzvah Klal Yisrael received as a nation, and is of great importance, as all of our Yamim Tovim are fixed according to kiddush hachodesh. It determines when we eat matzah, when we fast Yom Kippur and when we refrain from melachah.

Until 1,700 years ago, the beis din sanctified every Rosh Chodesh al pi hare’iyah, on the basis of evidence supplied by two witnesses who saw the new moon. Once the beis din confirmed that the two witnesses actually saw the new moon, that day was declared Rosh Chodesh and messengers were sent out to inform all Jewish kehillos that the new month had been declared.

Although we no longer sanctify the new month according to the testimony of witnesses, the second day of Yom Tov kept in chutz laaretz is a remnant of those times; since the beis din’s messengers couldn’t reach all kehillos outside Eretz Yisrael, the Jews in chutz laaretz were in doubt as to which day was established as Rosh Chodesh, and exactly when Yom Tov fell.

They therefore kept two days of Yom Tov, a minhag that continues to this day, even though there is no longer any question as to when Rosh Chodesh falls.

However, when the Sanhedrin is reestablished with the coming of Moshiach, we will return to fixing the months according to the sighting of the new moon.

The first problem that springs to mind is how to plan ahead: Without knowing exactly when Rosh Chodesh is, it will be much harder to plan bar mitzvahs and weddings.

But while we might be wondering how to write the date on our wedding invitations, there are others who have more important things in mind.

Dr. Roy Hoffman, an expert in moon observations, is worried: Who will have the expertise to sight the new moon? Although we all know what the moon looks like, Dr. Hoffman says that only those who are specially trained are able to observe the new moon early enough to be mekadesh it.

Experienced moon observers are able to see the new moon a day before the normal eye spots it, Dr. Hoffman says, and that day makes all the difference.

“While kiddush hachodesh according to observation is not practiced today, it is valuable to carry out calculations and practice observing the new moon in order to be ready for the reestablishment of kiddush hachodesh al pi harei’yah,” says Dr. Hoffman.

In fact, it is so hard to observe the new moon that Harav Shmuel Kalifa, an expert and lecturer in hilchos kiddush hachodesh, insists that the first thing the Sanhedrin will test the witnesses on is ... their eyesight.

“When the witnesses come to the Sanhedrin and claim they saw the new moon, the Sanhedrin will have to check their eyesight to verify that they are actually capable of seeing the tiny new moon,” Rav Kalifa says.

The Israeli New Moon Society was established to prepare Jews for kiddush hachodesh al pi hare’iyah. Of the 2,800 recorded moon observations that have been collected throughout the world, the society is the source for over 2,000 of them.

Society members observe and record the new moon each month, in order to determine criteria for the limits of visibility when Moshiach comes.

“There is still plenty of room to improve on the existing criteria, using observations and analyzing them in relation to physical, meteorological and physical parameters,” says Dr. Hoffman, a chemist by profession.

The Israeli New Moon Society, which was founded by Harav Nachum Eliezer Rabinovitch, Rosh Yeshivas Birkas Moshe, Maaleh Adumim, now has 280 registered members, with 20 sending new-moon-sighting reports every month.

“We have all kinds of Jews in our society - Jews from the whole spectrum of religious and political society,” says Dr. Hoffman. “We even have scientists and secularists, but all of them are ‘observant,’ “ he quips.

The society works with the Institute for Kiddush Hachodesh Studies, which is under the direction of Rav Shai Walter.

Dr. Hoffman says that the first step in observing the new moon is knowing exactly when and where to look for it.

“The moon is often extremely thin - it can be a mere line or even look like a smudge - and it requires practice to properly recognize the new moon,” Hoffman says. “If you don’t know where to look for it, it’s like looking for a needle in a haystack.”

In order not to find oneself in a haystack, Rav Shmuel Kalifa, an avreich in Kiryat Sefer, has created a computer program to calculate the exact spot and time the moon can be noticed.

But there is another hitch: The observers only have a short time to see the new moon before it sets.

“The new moon is usually seen from around 20 minutes after sunset until the setting of the moon, which is only about an hour later,” Dr. Hoffman says.

In order to help its observers, the Israeli New Moon Society offers diagrams, instructions and report forms to help locate the new moon.

“You have to find the moon the moment it becomes visible to the naked eye, requiring expertise - and the use of binoculars helps a lot,” Dr. Hoffman says. “Generally, an observer can develop the necessary skill after a few months of practice.”

Dr. Hoffman warns observers who are looking hard not to trick themselves by imagining that they have seen the moon. “We advise observers to make sure that they really saw it and didn’t just imagine seeing it, by diverting their gaze for a moment and then looking back to see if the moon really is visible,” he says, adding that once the moon has been found, the observer should ideally continue looking till it fades or sets.

By using binoculars, it is possible to see the moon 15 minutes earlier than with the naked eye, Dr. Hoffman notes, although he warns that beis din wouldn’t accept the testimony of someone who saw the moon through binoculars.

So why use binoculars?

 “It is easier to spot the moon with binoculars. Once the moon is located, the sighting can be confirmed with the naked eye.”

Hoffman adds that binoculars can be useful in confirming that the observer actually saw the moon in instances where he is unclear as to whether what was seen was the moon or something else.

Where are these observations made?

“It is best to find a place to look from where the horizon is unobstructed and where there are no bright lights from that direction.”

Rav Kalifa says it is important for moon observers to record where the moon was seen, and if it was easy or hard to see it.

“This way, we can verify if the spot is a preferred location for observing the new moon,” he explains.

According to Hoffman, the best place for new-moon observations is on Har Chizkiyahu, near Eilat. Har Chizkiyahu is the highest of the Eilat mountains, and is famed for its beautiful scenery: On one side you can see the whole Sinai; from the other is an even more spectacular view of the Gulf and a broad panorama including Eilat, Aqaba, Jordan and Saudi Arabia. On a clear day, you can see for miles in every direction ... including upward, which is why observers prefer Har Chizkiyahu.

As part of his instructions to new moon observers, Hoffman is careful to remind them that no chillul Shabbos may be involved when looking for the new moon.

“While the eidim who witness the new moon were allowed to leave techum Shabbos and take whatever actions necessary to reach the Sanhedrin, even if it meant chillul Shabbos, I have to warn present-day observers that these rules no longer apply until we once again fix the new month al pi hare’iyah,” Hoffman says.

Can you reveal when to look for the new moon next week?

(Dr. Hoffman smiles.) “I was waiting for that question. The coming Rosh Chodesh is Tuesday, Rosh Chodesh Nisan, but the moon will not be seen on Tuesday with the naked eye, although it may be seen in Israel with binoculars or a telescope.

“Instead, the moon will appear on Wednesday evening in Yerushalayim between 5:33 and 7:26, tilting to the right.

However, in Europe and the U.S. it may be possible to see the moon with the naked eye on Rosh Chodesh.”

How did you get interested in the lunar observations?

“11 years ago I was asked to write a scientific appendix for Rav Nachum Rabinowitz’s sefer, and when I started researching the subject of moon observing I realized that there wasn’t enough information about it.”

Dr. Hoffman relates that he once went with his family to Har Chizkiyahu to spot the new moon, even though the calculations showed that the new moon was just beyond visibility.

Indeed, they returned home the same night without having seen the new moon.

The next evening they returned to Har Chizkiyahu, and the moon was clearly visible.

As usual, they recorded the time, location and view of the moon, took photos and returned home.

However, on arriving home, they checked their photos and noticed that in a photo taken the previous night the new moon could clearly be seen!

The Old and New Moon

How do you know that what you are seeing is the new moon and not the old one?

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