Wednesday, September 16, 2015

The Nivreshes as an Indicator of Zman Kriyas Shema

How did a golden candelabra mounted on top of the Sanctuary Building let the people of Jerusalem know that it was time to recite the morning Shema?
Yoma 37b states that Queen Heleni donated a golden candelabra to the Temple which was installed over the entrance of the Sanctuary (on top of the building). When the sun rose in the morning, its rays would cause the candelabra to sparkle and this would be the signal to the people of Jerusalem that the time for reciting the morning Shema had arrived.

The ideal time to recite Shema is a few minutes before sunrise. Specifically, one should be finishing Shema and its after-berachah just as the sun comes up over the horizon so that one can then begin davening Shemoneh Esrei with the rising sun. In theory, then, placing a candelabra on top of a tall building would make a effective indicator, since the rays of the rising sun will strike the candelabra before sunrise is visible down on the ground.

Nowadays, it is possible to calculate the difference in time between when the sun struck the candelabra and when it was visible to the people on the ground, all without leaving the comfort of your swivel chair.

There are various websites which will give you sunrise times for anywhere on earth, although the time provided is often just for sea level. I needed an algorithm which takes elevation into account, and for that I turned to Mr. Stanley Fishkind, an author and lecturer on the topics of zemanim and astronomy (as well as a former NASA employee) who shared with me his spreadsheet for calculating zemanim. Here are some results from his spreadsheet:

Date Elevation (feet) Sunrise
March 21, 2015
2400
5:38:12
March 21, 2015
2550
5:38:04
June 21, 2015
2400
4:29:18
June 21, 2015
2550
4:29:09

The approximate elevation of the Temple Mount is 2400 feet above sea level, and the height of the Sanctuary is 150 feet. As can be seen above, at the equinox (March 21) the sun would strike the candelabra 8 seconds before being visible on the ground, and on the solstice (June 21) the time difference is 9 seconds.

In either case, the amount of warning that the candelabra provides is disappointingly small since it is clearly impossible to recite the entire Shema in 8 or 9 seconds. In practice, this means that anyone relying upon the signal of the candelabra would wind up starting Shemoneh Esrei a couple of minutes after sunrise instead of right at sunrise. If so, of what value is the signal of the candelabra?

This issue is addressed by Minchas Bikurim to Tosefta Yoma 2:3 who realized, either by calculation or intuition, that the difference in height between the candelabra and the ground was not enough to provide the 2-3 minutes of warning that the average person would need to recite Shema and its after-berachah. In short, he concludes that the candelabra was not meant to signal the ideal time for Shema.

The ideal time to recite Shema was, in Temple times, very difficult to gauge and only a select group, known as the Vasikin, were able to pinpoint it accurately. Most people, therefore, would wait until they actually saw the sunrise before starting Shema, even though this was a couple minutes after the ideal time. The signal of the candelabra was instituted to give the general public an advance warning — albeit a very short one, as it turns out — for sunrise so that they could recite Shema somewhat closer to the ideal time than they would have otherwise.

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