Zmanim May be Incorrect (Potential Issue of Shkia, etc.)

[Yochanan]

Hi:

I noticed recently that though in the past my zmanim had been
accurate, in line with the myzmanim website, recently it has listed
times, such as shkia, about 2 minutes after the true time.

I have downloaded the times a while ago and have not connected my iPod
to the internet in the last few months to update the zmanim.

Is this an issue in general or are the times off from the myzmanim
website only if the Siddur hasn't connected to myzmanim in a while?

Thanks for your help and all your good work.

Kol tuv,
Yochanan

[Barry Schwartz]

This is likely an altitude issue. I would override your altitude to
zero and it should match MyZmanim.

FYI, the zmanim are not downloaded, they are run based on an
algorithm, that plugs in your coordinates.

[Yochanan]

It turns out that that was the "issue", so in fact it's working just
fine. I have the same location plugged into my iPod 2 times, once
with altitude and once with 0 altitude, so that explains the roughly 2
minute difference (at about 113 meters). For some reason I thought I
was "sure" that I was looking at the zmanim for the 0 altitude when in
fact it was the zmanim for 113 meters. So, everything's fine.
Anyway, I was aware of the proper zmanim from another source at that
time.

Thanks for your good work and sorry for the misunderstanding on my
part.

Yasher Koach on all of your good work! :-)

Chodesh tov for you, your family, others at Rusty Brick, and all of
k'lal Yisrael,
Yochanan

GENERAL NOTE:

P.S. In general, being early for all the zmanim - especially Shabbos/
Yom tov, would help ensure, with Hashem's help, that a miscalculation
of a couple - several minutes in the zmanim wouldn't be a problem.
But, of course, precise zmanim are important if someone needs to
perform a melacha shortly before Shabbos. But even with precise
zmanim, if someone gets zmanim for a general location (i.e. city or
even a zip code) it could provide a time that might be even a couple
minutes off. Even with pretty precise times, Myzmanim.com notes that
"Do not rely on zmanim times to the last moment". So - even though
this is clear - the takeaway for individuals could be that the "last
minute" preparations that could be made for Shabbos/Yom tov that
should not be done once sunset comes, should try to be completed
before the "last moment" - with a "buffer".