More Discussions for this daf
1. Taurus and Scorpio 2. North-South Determination 3. The Vilna Gaon's calculation
4. Rav Ada 5. Tekufos - Halachic vs Secular 6. Vernal Equinox
7. Gra on Tosfos D"H Abaya 8. Rashi's Siman 9. Rashi's inexact calculation
10. Solistice? 11. Rashi, D"H v'Ein Tekufos Tamuz.. 12. Rashi DH Mipnei She'Mafsid - Where does the 28 come from?
13. Bach on amud beis 14. Constellations 15. Akrav is in the South
DAF DISCUSSIONS - ERUVIN 56

Q. Reese asked:

We are told that "Eglah (= Taurus, the Mazal of Iyar) is the northernmost of the zodiac constellations, while Akrav (Scorpio, the Mazal of Cheshvan) is the southernmost one."

Yet Rashi tells us that the day of Tekufas Tamuz was the longest day of the year (midsummer) and therefore the sun is the farthest north, and the day of Tekufas Teves is the shortest day of the year (midwinter) and the sun is the farthest south. If that is true, then the beginning of Sartan (Mazal of Tamuz) should be the northernmost of Mazalos, and the beginning of Gedi (Mazal of Teves) should be the northernmost point. Why, then, do Chazal say that Eglah and Akrav (two Mazals farther down the ecliptic!) are the most northerly and southerly Mazalos? Where did I go wrong?

Thanks for all of your very helpful answers to my past questions!!

Q. Reese, Atlanta, Georgia

The Kollel replies:

You have touched upon a very important point that has far-reaching ramifications.

When we say that the Mazal of Nisan is Tleh, it does not mean that the sun is actually to be found among the group of stars which look like a Tleh that lie along the ecliptic. Although there was a time in history when the sun was in Tleh on Nisan, that is no longer true!

The reason for this is because of what is called "the precession of the equinoxes." This phenomenon causes the sun to lag bit by bit along the ecliptic (due to a slight wobble in earth's orbit) until, after ~2000 years, it moves back one entire Mazal. That means that although the sun was beginning Nisan at Tleh when Yakov went down to Egypt, by the time of the Churban the sun was lagging by about .75 Mazalos (i.e. it was towards the beginning of Dagim), and by today it is lagging by 1.75 Mazalos (i.e. it is towards the beginning of Dli).

That does not change the way we look at the Mazalos of the months. We still say that Mazal Nisan is Tleh. In fact, the Rambam defines Tleh as the Mazal that begins at the vernal equinox (or the point at which the sun crosses from the north to the south of the ecliptic). This means that no matter what formation of stars actually lies behind the sun, we refer to that point along the ecliptic as the beginning of Mazal Tleh. (There is, in fact, dissent among astrologers as to which Mazalos to use nowadays for practical astrology.)

In any case, when it comes to looking at the sky for a group of familiar stars, today the end part of Mazal Shor (i.e. beginning of Te'omim) is in the northernmost part of the ecliptic, and Akrav (or beginning of Keshet) in the south.

Alexander Schutz, Kiryat Sefer

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