RAkiva Miller wrote:
 
<<My LOR (listmember Rabbi Elazar Teitz of Elizabeth NJ) follows an
interesting mix of keeping things simple so as not to confuse people,
and also allowing some variations: For most of the year, the official
Motzaei Shabbos is at 45 minutes after shkiah. But for all of May,
June and July, we end at 50 minutes. We sacrifice a little bit of
accuracy for the sake of simplicity. (Or maybe we sacrifice a little
simplicity to end Shabbos five minutes earlier for nine months of the
year?)

On the other hand, all fasts - both winter and summer - end at 42
minutes, except for Yom Kippur which ends at 54 minutes.>>
 
To which REli Turkel responded:

<After the various answers I am still confused. According to this
Taanit Esther ends some 3 minutes before the time for Motzei Shabbat.
This corresponds to my memories of the US. However, as Michael
Kopinsky also confirms in EY the fast ends 10-20 minutes before the
time for motzei shabbat>

     In Yerushalayim, there are apparently three times for tzeis
hakochavim: 17 minutes, which is the time after sunset that the
earliest ma'ariv is begun; approximately 25 minutes, which is the time
for ending ta'anios d'rabanan; and approximately 38 minutes (which may
vary slightly by season), the time generally posted for Motza'ei
Shabbos, and used by those who do not wait 72 minutes.  The 25-minute
z'man is listed in the Tikotzinsky luach (which is the wall luach for
the shuls) for one motza'ei Shabbos as well: Chanukah, since the minhag
in Yerushalyim, in accordance with shittas haGra, is to light at sunset
during the week, and as soon after Shabbos as possible. Apparently, the
25-minute period is considered to be true tzeis, and though in other
weeks there is an addition, either as a chumra or as tosefes, it is not
done when it would interfere with proper kiyum of ner Chanukah. (More
accurately, that was the situation 50 years ago.  I don't know whether
it is still the listing for motza'ei Shabbos Chanukah.)

EMT



-- 
Eli Turkel