(part2)
Rabbi Shimon ben Pazi said that Rabbi Yehoshua ben Levi said in the name of bar Kappara: Anyone who knows how to calculate astronomical seasons and the movement of constellations and does not do so, the verse says about him: “They do not take notice of the work of God, and they do not see His handiwork” (Isaiah 5:12).
And Rabbi Shmuel bar Naḥmani said that Rabbi Yoḥanan said: From where is it derived that there is a mitzva incumbent upon a person to calculate astronomical seasons and the movement of constellations? As it was stated: “And you shall guard and perform, for it is your wisdom and understanding in the eyes of the nations” (Deuteronomy 4:6).
What wisdom and understanding is there in the Torah that is in the eyes of the nations, i.e., appreciated and recognized by all? You must say: This is the calculation of astronomical seasons and the movement of constellations ...
shekinahcancook