The Astronomical Book · First Enoch

Chapter LXXII

The Book of the Courses of the Luminaries of Heaven — R.H. Charles Translation

The sun traverses six portals in the east and six in the west, completing its annual course in 364 days. Day and night are measured in eighteen equal parts. An intercalary day is added at the close of every third month, giving four seasons of exactly 91 days. At each solstice the sun reaches the extreme of that portal and works back through the portals in reverse order.

Spring (outward, Gates IV→VI)
Summer (return, Gates VI→IV)
Autumn (outward, Gates IV→I)
Winter (return, Gates I→III)
Day portions (of 18)
Night portions (of 18)
† Intercalary (31-day month)
Month /
Period
Portal
(East Rising)
Days
(Exact)
Key
Verses
Light Balance (of 18 Parts) Seasonal Point (as described in text)
◈   Spring — Sun ascending northward through portals IV → VI
1 IVFourth (great portal) 30 mornings 6–9
10
8
10 day · 8 night
Start of Year Day starts lengthening — Vernal Equinox implied (balance point)
2 VFifth 30 mornings 11
11
7
11 day · 7 night
Days continue lengthening
3 VISixth 31 mornings 13–14
12
6
12 day · 6 night
Summer Solstice Longest day — extreme north (Gate VI). Sun turns here.
◈   Summer — Sun descending southward through portals VI → IV (return pass)
4 VISixth (return pass) 30 mornings 15–16
11
7
11 day · 7 night
Post-solstice — day decreases to 11 parts. Days start shortening.
5 VFifth (return) 30 mornings 17–18
10
8
10 day · 8 night
Continued shortening
6 IVFourth (return) 31 mornings 19–20
9
9
9 day · 9 night
Autumnal Equinox Balance restored — equal day and night (9:9)
◈   Autumn — Sun descending southward through portals IV → I
7 IIIThird 30 mornings 21–22
8
10
8 day · 10 night
Nights now longer than days
8 IISecond 30 mornings 23–24
7
11
7 day · 11 night
Continued shortening of days
9 IFirst 31 mornings 25–26
6
12
6 day · 12 night
Winter Solstice Shortest day — extreme south (Gate I). Sun turns here.
◈   Winter — Sun ascending northward through portals I → III (return pass)
10 IFirst (return) 30 mornings 27–28
7
11
7 day · 11 night
Post-solstice — night decreases to 11 parts. Days start lengthening.
11 IISecond (return) 30 mornings 29–30
8
10
8 day · 10 night
Lengthening continues
12 IIIThird (return) 31 mornings 31–32
9
9
9 day · 9 night
Year End 364 days complete — balance restored (9:9). Cycle renews at Gate IV.
Annual Totals 364 days vv. 6–32 18 parts per day · 4 intercalary days · 4 × 91 days per season Portal arc: I ↔ VI · Two solstices · Two equinoxes

Intercalary days — An extra day is appended at the close of months 3, 6, 9, and 12, yielding four quarters of exactly 91 days (30 + 30 + 31 = 91). Four quarters × 91 = 364 days total. Significantly, this 31st day is not reckoned in the ordinary count, placing it outside regular time. This suggests it functions as the day of the boundary — the precise moment the sun stands at the extreme of its portal before reversing course. At Month 3 (Gate VI) it marks the summer solstice turning point; at Month 9 (Gate I) the winter solstice; at Month 6 and Month 12 the equinox threshold between Gate III and Gate IV. A day outside the count belongs to neither the outgoing nor the incoming arc — it belongs to the boundary itself, consistent with ancient Near Eastern practice of treating the four cardinal solar points as days apart from ordinary time.

Portal reuse at solstices — At each solstice the sun reaches the extreme of that portal and works back through the portals in reverse order. At the Summer Solstice (Gate VI, Month 3), the return journey begins in Gate VI again for Month 4, then steps back through V, IV. Likewise at the Winter Solstice (Gate I, Month 9), Month 10 also rises in Gate I before ascending through II, III. The solstice portal is thus used for two consecutive months — the turning month and the first return month — before the arc resumes.

Light balance — Parts are of 18 equal divisions of the 24-hour period. At Summer Solstice: 12 day / 6 night. At Winter Solstice: 6 day / 12 night. The vernal equinox falls between Gate III and Gate IV — a portal boundary rather than a gate itself. Month 1 already shows 10:8 because the sun has crossed the equal-day point in the unmarked transition from Gate III to Gate IV and is climbing northward. The true equal division (9:9) at Month 6 and Month 12 reflects the return crossing of that same threshold, where the month-end measurement lands precisely on the balance point.

Source · 1 Enoch 72 · Trans. R.H. Charles, 1913 · The Astronomical Book