Halakhah su Levitico 25:9

Eastern scholars¹ These are Hindu scholars (commentary to Leviticus 25:9). said that the solar year has an excess of 1⁄120 of a day, beyond the ¼ of a day that is in addition to the number of full days (365).² Thus a solar year is 365 + ¼ + 1⁄120 days, or 365 days, 6 hours, and 12 minutes, approximately 365.2583 days. Persian scholars said that the excess is 1⁄115 of a day.³ According to the Persian scholars a solar year is 365 + ¼ + 1⁄115 ~ 365.2587 days. Chaldean scholars said that the excess is 1⁄170 of a day.⁴ 365 + ¼ + 1⁄170 ~ 365.2559 days. Greek scholars said that the solar year is deficient by ⅓00 of a day from ¼ of a day.⁵ 365 + ¼ – ⅓00 ~ 365.2467 days. This value for the solar year was obtained by Hipparchus about the year 135 b.c.e. (Almagest iii, 1, p. 137; see Evans, p. 209). Recent scholars, and they are many, said that the deficiency is 1⁄106 of a day;⁶ These are certain Arab scholars (Sefer haMoladot, p. 240). According to their calculations a solar year is 365 + ¼ – 1⁄106 ~ 365.2406 days. others say 1⁄110 of a day.⁷ Other Arab scholars (Sefer haTa‘amim ii, p. 44). Thus a solar year is 365 + ¼ – 1⁄110 ~ 365.2409 days.

Judah the Persian¹⁹ Mentioned by Ibn Ezra in his Commentary to the Pentateuch and elsewhere. Nothing is known of this scholar. (See Encyclopedia Judaica, second edition, vol. 11, p. 505.) said that the years used by Israel were solar years, because he found the festivals were on fixed dates: Passover when the barley ripens (Exodus 34:18), Pentacost at reaping time (ibid. 34:22), and Tabernacles at harvest time (Deuteronomy 16:13). However, what can be done since Moses did not specify the length of a year?²⁰ Since the Bible does not specify the exact length of a solar year, the Karites are left with the matter being undecided. This will also affect determination of the festivals. Also, how will he explain the use of the Hebrew term “hodesh” (new) for “month,” for what is renewed relative to the sun? The uncircumcised (Christians), because their years are solar years and they found that a full year contains twelve lunations, divided the days of the year into twelve parts, for this number is closest to the number of lunar months. The result is that some months are 30 days and some months are 31 days.²¹ Here Ibn Ezra accounts for the division of a year into twelve parts, even if one uses a solar calendar. However, the term “hodesh” would not be appropriate for such solar months.

Therefore, natural philosophers said that by right the year should begin with the point of intersection (equinoctial point) from which the sun begins to approach the inhabited portion of the earth (the northern hemisphere).⁷³ This is a “tropical year,” the period from one vernal equinox until the following vernal equinox. This is the cycle of Rav Adda.⁷⁴ Rav Adda’s year is a tropical year. Although his cycle is based on the average orbit, its correction is simple.⁷⁵ Rav Adda’s figure is for a mean solar year. Corrections need to be made to accommodate apparent variations in the solar orbit. This was also the beginning of the year for those who developed the Hebrew calendar. This was also the beginning of the year for the early Greeks.⁷⁶ See Evans, pp. 182–184 for a discussion of early Greek calendars. This is the vernal equinox. The Persians begin their year with the summer solstice, the Chaldeans with the autumnal equinox, and the Christians with the winter solstice. However the Christians are in error since their calculation of the solar year is not correct.⁷⁷ During the lifetime of Ibn Ezra, Christians followed the Julian calendar, with a year consisting of exactly 365¼ days. In the year 1582 the Church reformed its calendar and adopted the Gregorian version, improving upon the approximation of the Julian calendar.