Calculating the true astronomical North/South is very simple - find the longest way and cast a shadow.

Are there sources on how precise those directions in the Temples were? Are there special Jewish calculations? Is there a tradition of pointing to a certain landmark (a point on Mt. Olives) or aligning with the stars?

(for comparison, "The [Egyptian pyramids] tombs are aligned north-south with an accuracy of up to 0.05 degrees.")

  • There are walls on the Temple mount visible to satellites that are uncannily aligned with the cardinal directions. Can't prove anything without archaeology of course.
    – Double AA
    Commented Jun 16, 2019 at 13:27

1 Answer 1


Yerushalmi Eruvin 33a:

כמה יגעו נביאים הראשונים לעשות שער המזרחי שתהא החמה מצמצמת בו באחד בתקופת טבת ובאחד בתקופת תמוז.

How much effort the early prophets put in to make the eastern gate [of the Har Habayis] such that the sun would shine exactly through it on the first day of the winter season and the first day of the summer season.

See also Bavli Eruvin 56a, that similar methods can be used when measuring the techum of a city.

  • Great! 2. מצמצמת=shine? מצמצמת what, its rays? a very strange use for this word. Wait, טבת and תמוז? That's summer and winter: תקופת ניסן: 7/8 באפריל, and תקופת תמוז: 7/8 ביולי and תקופת תשרי: 7 באוקטובר and תקופת טבת: 6/7 בינואר, Why?
    – Al Berko
    Commented Jun 17, 2019 at 18:00
  • 1
    @AlBerko מצמצמת would mean to fit exactly (no overlap on either side). תקופת טבת and תקופת ניסן (according to Shmuel's calculation) nowadays are on those dates, but back then they were better aligned with the actual astronomical dates.
    – Meir
    Commented Jun 17, 2019 at 18:02
  • Do you mean like מצטמצמת?
    – Al Berko
    Commented Jun 17, 2019 at 18:04
  • But that seems impossible, it has to be in the same position, i,g, 21/3 and 21/9
    – Al Berko
    Commented Jun 17, 2019 at 18:05
  • 1
    @AlBerko מצטמצמת would be reflexive (fits itself exactly); מצמצמת is transitive (makes something else - its light - fit exactly). Not sure what you mean with your second comment, but the neviim weren't necessarily using approximations such as Shmuel's tekufah - they might have used more precise calculations, similar to Rambam in Hilchos Kiddush Hachodesh.
    – Meir
    Commented Jun 17, 2019 at 18:14

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