Halakhah for Berakhot 52:9

Astronomers begin the day with midday and it extends until midday of the following day, twenty-four hours. This is a complete day for their calculations. This is justified for their need because of two factors, which only geometers can understand.¹ Among the advantages of defining a day as extending from midday to midday (or midnight to midnight) is the fact that all inhabitants along a common meridian would begin and end the day at the same time. This is not the case if a day extends from sunrise to sunrise or from sunset to sunset. Also, from midday to midnight will always be 12 hours, which is not the case from sunrise to sunset. However, since the shadow at midday is always short and slants only slightly, sometimes an individual’s eye cannot discern this. Even with a sundial or an astrolabe, a scholar cannot recognize the moment of midday. Therefore our Rabbis found it necessary to tell us that the Minha prayer should be one-half hour after midday, for then the eye can discern that the sun has passed to the west. For this reason it is unlikely that midday should be the beginning of the day. All the more so with midnight, for no person can know it.

It is permissible le-khatḥila to pray in the plaza of the Kotel (the Western Wall) because it is surrounded by walls on three sides. Moreover, the holiness of the site reinforces one’s love and awe of God, causing one’s prayer to be said with more kavana. The patriarch Yitzḥak did this when he recited Minḥa on Mount Moriah, which was then an open field, as it says: “Yitzḥak went out to meditate in the field” (Bereishit 24:63; Berakhot 26b; Midrash Tehillim §81).

That is that He commanded us to read the recitation of Shema in the evening and the morning. And that is His saying, "and you shall speak about them" (Deuteronomy 6:4). And the regulations of this commandment have already been explained in Tractate Berakhot; and there (Berakhot 21a), it is explained that the recitation of Shema is [an obligation] from the Torah. And it is written in the Tosefta (Tosefta Berakhot 3:1), "Just like the Torah established [a set time for] the recitation of Shema, so too did the Sages establish a time for prayer." This means to say that the times of prayer are not from the Torah - though the actual obligation to pray is from the Torah, as we explained (Sefer HaMitzvot, Positive Commandments 5) - and the Sages, may their memory be blessed, arranged times for them. And this is the content of their saying (Berakhot 26b), "They established the prayers corresponding to the daily sacrifices" - meaning, that they fixed their times according to the times of the sacrifices. And women are not obligated in this commandment. (See Parashat Vaetchanan; Mishneh Torah, Reading the Shema 1.)