[Avodah] A Question About Davening Vo'Sikin

[David E Cohen]

R' Prof. Yitzchok Levine wrote that:
> I have from time to time davened with Vo'Sikin minyanim where the
> attempt was made to start Shemoneh Esrei precisely at Netz.

I used to daven with a minyan that had a chart on the amud listing the time
of sunrise to the nearest second, and the custom was to try to start
shemoneh esrei exactly then (which most of the regular ba'alei tefilah
successfully learned to be able to do "naturally," without awkward long
pauses before "Tzur Yisra'el").  I thought this level of precision a bit
strange, since the seconds are not really a "significant figure" in
calculated sunrise times.  The time of the visible sunrise can vary by close
to a minute (at the temperate latitudes) from the calculated average, since
the amount of atmospheric refraction varies with the pressure and humidity.
This is besides the fact that many of the computer programs that generate
these charts don't take the altitude of the observer and the altitude at the
horizon into consideration.  (Some posekim don't consider either, some
consider only the former, and some consider both.)

I think that the time generated by a calculation that uses the average
atmospheric refraction is best viewed as an average, meaning that one can
best "play it safe" by finish keri'as shema a minute before that and
beginning shemoneh esrei a minute after that.

In any case, it seems from the gemara that the "vasikin" were more
interested in saying kerias shema before sunrise (and still being someikh
ge'ulah li-tfilah without having to daven before sunrise) than they were
with davening shemonei esrei at the earliest possible "likhatechilah"
moment.

-- D.C.