[Avodah] zman hadloko erev Shabbos and motzoei Shabbos

[Zev Sero]

Marty Bluke wrote:

> 
> R' Tam's shita has always really bothered me. The Gra's question of
> "hachush makchish" is so powerful and obvious I don't understand how
> the Rishonim  could have said what they said. Did they never go
> outside an hour after sunset and see that it was pitch black and
> you could see hundreds of stars?

They might have thought that perhaps all of those stars were "kochavim
gedolim", and not the three "kochavim beinunim" that are required.
The reason Chazal gave us the shiur in time (the time it takes to walk
X millin, the time it takes to climb down Mt Carmel, etc.) is that we
(i.e. the people of their time and place) are not expected to know
exactly what magnitude of star they considered to be "beinuni", whereas
we can observe how dark it is so long after sunset at the equinox, and
judge on any other date whether it's that dark.

The truth is that something approximating "Laila DeRT" does match a
real phenomenon -- when the sun is 18 degrees below the horizon none
of its light is still in the sky, and it's as dark as it's going to
get.  This is what the charts call "astronomical twilight".  Which
sounds very like what one might figuratively call the sun leaving
the "thickness of the sky", or the "second sunset".  But it's clear
from that description that the stars which become visible at that
time are not "beinunim" but "ketanim shebiktanim"; any star that
you can't see at astronomical twilight, you will never see at all
(given the same eyes, equipment, and light pollution, of course).

That is why Shu"T Bnei Tzion, in vol 2, tries to argue that RT never
held of "shitas RT", that he was misunderstood throughout the years,
and he meant that Bein Hashmashos was the *first* 3/4 mil, not the
last, exactly like everyone else; his only point, according to this
theory, is that while it's already "vadai layla" the sun is in fact
still in the "sky", i.e. its light is still being refracted into
the atmosphere, and it doesn't "leave the sky" until after 4 millin.
It is rather difficult, though, to actually read this into RT's words,
and impossible to do so with all the rishonim and achronim who followed
(what they believed to be) his shita.

-- 
Zev Sero               Something has gone seriously awry with this Court's
zev at sero.name          interpretation of the Constitution.
                       	                          - Clarence Thomas