[Avodah] Where is the Molad announced for?

[Micha Berger]

On Thu, Dec 24, 2020 at 08:02:09PM +0200, David Cohen via Avodah wrote:
> As far as my main point, I share your objection to the assumption that the
> calendar moladot were intended to be referring to Jerusalem mean time.  I
> just don't think they were intended to be referring to the exact mean time
> of any deliberately selected meridian, but rather that the determining
> factor was having the very first molad come out exactly on the hour.

Ah, a fourth option. Quoting the first three from my previous post:

> 1- Explain it is okay for the time of the molad to be 15-22 min off in the
>    days of chazal, and stick to the common belief that the time is
>    Y-m local.

> 2- Use for the meridian where the local clock is 15 min 22 sec later,
>    so the minimum error (164bce) is zero. That's 4 deg 7 min east of
>    Yerushalayim, which is about 1/3 of the way to Bavel.

> 3- Use the meridian where the local clock is 22 min 25 sec later, so
>    that the error between astronomy and the *time* of the halachic
>    molad was zeros at the end of Chazal's day. 

And now:
4- Use the meridian that gives the first Molad an even 8am the Friday
   Adam was created.

(Note for third parties: Molad Baharad [meaning Yom Shini, 5 hours and
204 chalaqim] is the year before, the Molad for a hypothetical Tishrei
of year 1, on the Monday of a year 0. Which makes the math easier,
since you don't have to subtract anything from the year number to start
calculating. but it's a molad that if Bereishis 1 is literal days,
couldn't have happened -- no earth or moon yet. thus the other name:
"Molad Tohu", the molad during Bereishis 1:2.)

Takeh, that is very telling.

Given that the first Molad is almost certainly back-calculated, and
it's unlikely R Yosi ben Chalafta got every question and machloqes
about dating and years historically correct. (As I've said before,
"shenas 5781 leminyan she'anu monim kan" doesn't make an iqar emunah
that we are monim correctly over here, and in fact may imply we are
conceding we aren't sure.)

If I had confidence it were historically accurate, I could equally say:
the round number may imply HQBH picked that meridian when Creating. And
then there would be a significance to the meridian even with your
core theory.

(Maybe even it points to the meridian of Gan Eden, if it was on earth.)

> There's a wide range, spanning 15 degrees of longitude, over which rounding
> that first molad to the nearest hour would get you the same result (14
> hours into Friday), and I doubt that it particularly interested anybody at
> the time the calendar molad was established to figure out exactly what
> meridian it would be precisely accurate for.  For the purpose of the
> calendar, it doesn't matter.  We only need to know if we want to translate
> the molad into an actual time that we can point to on our watches and say
> "the molad is.... now." ...

The point of Mevorkhim haChodesh (a/k/a Hahrazat haHodesh) and making
sure to be aware of the time of the molad when doing so is to commemorate
Qiddush haChodesh by the Sanhedrin. So, however the Sanhedrin referred
to the molad when setting up the rules for dechiyot when they switched
us to al pi cheshbon would serve the purpose. Any convention would do;
but better the one they did.

(The Magein Avraham says this is why we're standing, like beis din
accepting eidim. Except, RAEiger asks, they /didn't/ stand for eidus for
RCh! It's possible we're standing like the eidim, declaring the time
of the future RCh as a commemoration of everyone in the room saying
"MeQudash! MeQudash!")

I was arguing that R Hillel and his beis din would likely use some
contemporary time when setting up the calendar.

So as to keep the lede on top, I replied first about the *time* of
the molad. Jumping to RDC talking about the *interval*:
> The length of the mean synodic month (expressed in mean solar days***) is
> decreasing *very* slowly, such that it takes about 10,000 years to decrease
> by an entire chelek...

Which does mean that the most accurate time for the molad interval is
less than rounding error. It was but one factor out of what I thought
was a three-way "coincidence" that commended looking for the "right"
meridian in the days of R Hillel's beis din. The fact that it was their
time is much more significant (although less "coincidental"). And it
makes sense to announce the time at a meridian just around the middle
of where Jews then lived.

Might even be what the Rambam means, when he talks about the region eidim
may come from. Even if eidim weren't actually going to try arriving from
Bavel (and on time?!). The Rambam sticks in my craw still.

You can dismiss the significance of the "most accurate molad interval"
third of the "coincidence" without changing much of my argument. Which
is why I wanted to separate it out of the conversation of what clock the
molad *time* is from the topic of the accuracy of the molad *interval*.

Tir'u baTov!
-Micha

-- 
Micha Berger                 It isn't what you have, or who you are, or where
http://www.aishdas.org/asp   you are,  or what you are doing,  that makes you
Author: Widen Your Tent      happy or unhappy. It's what you think about.
- https://amzn.to/2JRxnDF                      - Dale Carnegie