16:
We have established so far that our mishnah sets the earliest possible time for reciting the Shema 'at the end of the day' at "starrise". This, of course, is a variable; for the time when three stars will be visible in the night sky will depend (among other imponderables) on the state of the weather, the eyesight of the spectator and the magnitude of the stars. To further complicate matters, the sages are wont to distinguish between 'small' stars, 'medium' stars and 'large' stars. It is obvious that since they could have had no concept of magnitude, they must be referring to the luminosity of the stars. Clearly, the visibility of stars is intended to indicate varying degrees of the onset of darkness. 'Large' stars don't count, because they can be seen even before it is dark. The end of Shabbat (which requires an additional amount of non-sacred time to be added on to the sacred time of Shabbat [tosefet]) requires the visibility of three 'small' stars. For the purposes of reciting the Shema 'at the end of the day' the visibility of three 'medium' stars suffices.

17:
When we try to give these indications quasi-scientific determinae, we usually describe them in terms of the sun's declination below the horizon. Three medium stars are deemed to be visible when (at any given geographic location) the sun has declined 5.88° below the horizon; three small stars are deemed to be visible when the sun has declined 8.5° below the horizon. In 'real' terms the former occurs about 25 minutes after sunset and the latter about 40 minutes after sunset. (This explains why it is possible on motza'ei Shabbat [Saturday night] to recite the Evening Shema [= Evening Service] before the time for Havdalah.)

To be continued.

M Scott Kramer writes:

Thank you for what I hope with be a most interesting and needed forum, particularly for those of us like myself with minimal Jewish education who want to know and study more. I have a lot of questions but am unsure as to the level of this forum. I have not studied Mishnah or Talmud before and my questions may not seem relevant but hope to catch on quickly. The one question I have up front with regards to the passage given to us in Berakhot 001 is: I thought the priests in the temple recited the Shema. Was it the whole Shema as we know it or a condensed form? By the whole Shema I mean the berakhot before and after as well as the three main paragraphs of the Shema proper. Or did it develop from some minimal recitation such as the first line of the Shema only? Would this indicate why the discussion seems to center on when the Priests ate their offering?

I respond:

Contrary to my usual custom, I have brought Scott's message in full. Over the past few days more than one hundred people have newly subscribed to RMSG and they too probably share Scott's uncertainty. So let's state clearly: no prior knowledge is assumed or expected, all questions arising from our learning and discussion are legitimate. If I think they are of general relevance I will post them and respond 'on-line'; if I think they are of a more limited relevance I shall respond by personal e-mail. (Please allow for a few days grace for both kinds of response.)

Now to Scott's question: the priests did, indeed, include the recitation of the Shema in the daily liturgy of the Bet Mikdash. The first mishnah of Chapter Five of Tractate Tamid reads: