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How can one calculate Jewish sunrise and sunset? I'm not necessarily asking for a formula. Just wondering if there's a difference between Halachik rise/set and what the world considers [e.g. science] rise/set, and if there is, what the difference is?

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related: judaism.stackexchange.com/q/1284/759 – Double AA May 21 '12 at 15:01
"between Haalachik rise/set".....and scientific rise/set? – Double AA May 21 '12 at 15:03
@DoubleAA Thanks for that. Edited to correct. – yydl May 21 '12 at 22:16
up vote 2 down vote accepted

Although there is some discussion in the poskim about these questions, for practical purposes, one should use the regular times for sunrise and sunset listed for your locale. These times can be found in local newspapers or on the internet. It is best to adjust these times approximately two minutes, because astronomical conditions and slight variations in longitude between your exact location and the sites at which the sunrise/sunset calculations are made. A good website for these calculations is kashrut.com/zemanim.

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myzmanim.com also has some good information – Menachem May 21 '12 at 4:07
related: judaism.stackexchange.com/q/13226/759 – Double AA May 21 '12 at 15:02
Agreed that the dominant position is that halachic sunrise/sunset are the ones generally called such. FYI, Rabbi Emanuel Gettinger shlit'a happens to be a very significant halachic figure (and an amateur astronomer) who dissents on this. – Shalom May 22 '12 at 0:54

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