Yima Epoch

«Yima epoch» coincides with midnight between the 16th and 17th day of the year 3102 B.C. (or, ˗ 3101) for the meridian of the Cupola of the earth.

1. According to the Persian astronomers, the conjunction of all “planets” marks the beginning of a period of 360 000 years. Notice that the epoch of Kali Yuga is just one day after the Persian date. But Indian astronomers generally reckon expired (Skt. gata) years (and days), and Persians current (OPers. θakata, Skt. vartamāna) years and days.

2. Yima epoch is connected with bad Winters (Av. aγәm zimō), the winters established by the Daēva which will come over the material world of life.

3. The time shown in the tables and calculations of the Persian Royal Zīgs was the mean solar time of a central point of longitude, called “Copula of the world” (Pers. gumbad ī gētīg, Arab. قبّة الأرض ). The meridian that passes through a pass near Kāzerōn in Persis was used as the origin of longitude by some Persian astronomers. Its longitude is 51° 30' East from Greenwich, and its latitude is 30° North. The Indian Siddhāntas use the mean solar time of Ujjainī on the meridian of Laṅkā, a place on the equator.3 Its longitude is 75° 46' 6'' E and its latitude 23° 9' N.

4. The Julian date equivalent for the epoch – 3101 February 17.0 from Gumbad is 588 464.36.
YD 0 (Yima day 0) = 588 463.36 JD.

5. The epoch day is a Thursday. Let Thursday, n = 0; Friday, n = 1; Saturday, n = 2; Sunday, n = 3; Monday, n = 4; Tuesday, n = 5; Wednesday, n = 6. To find the day of the week, we first find the Yima day (rōzān mar, Skt. ahargaṇa) corresponding to 0h GumbadMT on the day in question. Then, n = [YD – 1]7