[Avodah] The Molad of Tamuz

[Simon Montagu]

On Sun, Jul 1, 2018 at 11:59 PM, Zev Sero via Avodah <
avodah at lists.aishdas.org> wrote:

> On 01/07/18 13:39, Richard Fiedler via Avodah wrote:
>
>>
>> In other shuls the Molad was announced as _*Thursday*_, 0 hours and 97
>> chalakim. Such is the traditional way the Molad was announced. Minutes are
>> not used. >
>> Now I doubt that many would say  Elu v’Elu here. One of these
>> announcements was wrong.
>>
>
> Your entire discourse about sunset is irrelevant.  Sunset has absolutely
> nothing to do with *any* calculation of the molad.   The period between one
> molad and the next is always the same, therefore it should be obvious that
> there are no variable factors in its calculation, such as sunset.  The
> "day" for the calculation as the sources give it  (starting with Molad
> BaHaRaD) begins *not* at sunset but at precisely 6:00 PM. But 6:00 PM
> real time, not Standard Time, which is an invention of the US railroads.


Today I Learned that this is a 2x2 mahloket. RZS's "The period between one
molad and the next is always the same" and "the 'day' ... begins ... at
precisely 6:00pm" is the shita of the Levush (end of OH 428. All sources
quoted from the Itim LaBina luah, I haven't had time to check them inside).
There is then a sub-mahloket what we mean by "6:00 pm" -- is it 6 hours
after a mean "noon" which is the same all year around (shita of R Yona
Merzbach) , or 6 hours after astronomical noon on that particular day
(shita of R YM Tokaczinsky)?

According to RZS's statement "The period between one molad and the next is
always the same, therefore it should be obvious that there are no variable
factors in its calculation", we would say the first. But then we would not
always arrive at 6:pm "real time"! (Assuming that "real time" means
"sundial time", rather than "local mean time"). And maybe it's not so
obvious that the period is always halachically the same. Astronomically it
certainly isn't always the same -- even before the molad got longer,
29:12:793 was only an average figure.

Going back to the top-level mahloket, there are rishonim that go even
further in making the halachic molad a variable period. The Tosefot haRosh,
(Berachot 3b s.v. Keivan) and the Tashbetz (I:109) say that hour 0 of
"molad time" is always sunset. RRF's "as a real time ... I would state this
in Israel Summer time of 7:50 PM and 7 chalakim" fits this shita.

But here again there is a sub-mahloket on the calculation of the hours and
halakim: according to the Rosh and the second opinion in the Tashbetz we
use the same sha`ot zemaniot that we use for all other halachic times: 12
equal hours from sunset to sunrise, and 12 differently equal hours from
sunrise to sunset. According to the first opinion in the Tashbetz we use 24
equal hours, starting from sunset, and this is followed by the Mahatzit
Hashekela and the Eliyahu Zuta.

For this Tammuz, there isn't much difference between the second two
sub-shitot, but next month the difference is considerable: molad Av is at
12 hours 890 halakim, or 6:49 am, 8 halakim. By the first shita this
translates to 6:40am; by the second to 8:36, almost two hours difference!
(Again, all this is copied from Itim LaBina, I haven't attempted to verify
the calculations).

Personally I found all this very surprising, since like Zev, I had always
thought that the whole molad calculation system was based on its own time
framework with a rigid constant period of 29:12:793 between one molad and
the next, a rigid cycle of years of 12 months and years of 13 months, and
no variable factors.
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