﻿ moon-table

15/04 MOON  OF ANGKOR WAT

Ecliptic longitude from Sun = 33.27° at true midnight ie at 23:56:14 local civil time  April 15 Julian 967 AD

(Meridian of Phnom Bok)

OBSERVER(1) : north-west corner of the Naga terrace of Angkor Wat  (13.413658°N  103.864975°E)

DEFERENT

MEAN EQUANT

TRUE NORTHERN EQUANT (2)

TRUE SOUTHERN EQUANT (2)

MOON

Coordinates

of centre:

13.413658°

103.864975°

=    238.695 m

The centre (the observer) is located on the north-west corner of the Naga Terrace.

The loxodrome from mean equant of Chau Srei Vibol Sun to Phimeanakas is tangent to the deferent.

The intersection of the deferent with the causeway is located  on the loxodrome from East Mebon to observer. The azimuth of this loxodrome (31.399° from observer to Mebon) indicates the location of the Moon (31.444° from Sun) when it crossed its true (real) apogee on 10 / 04 / 967. The error is small (0.045°).

The two loxodromes running through the moat's north-west corner and tangent to the deferent cross the outer eastern and southern dykes on, respectively, the parallel and the meridian of the temple's geometrical centre.

The tangent which intersects with the east moat has an azimuth of 23.65°.

The obliquity was 23.574° on 15/04/967 and 23.552° on 15/04/1119

Error on 15/04/967 = 0.08°

Error on 15/04/1119 = 0.10°

The bisectrix of the angle created by the tangents is practically (error = 0.38°)  the diagonal running through the moat’s corners.

The diagonal is 1970 m long.

1970 m = 1131 phyeam

= 2** 180 phyeam

So, diagonal’s length = perimeter of a circle having a radius of 180 phyeam (10 kas).  This radius is equal to the distance from mean equant to IM (column “true southern equant”)

The continuation of this  diagonal (azimuth = 41.184°) runs through the equant of the 15/04 Saturn and through the temple of Banteay Chmar (41.308° ; error = 0.25°) .

Coordinates (centre of evection epicycle)

13.413768 °

103.865189 °

Distance from observer (c) =  26.148 m (15.012 phyeam)

Azimuth (as seen from observer) =  - 27.616°

The loxodrome from observer to mean equant  runs through the centre of a circle (“C”) which crosses the Phnom Bok observer, the Bayon, the central tower of Angkor Wat (and the equant of the Chau Srei Vibol Sun).

Coord. of centre of “C”:

13.443063°

103.9227988°

Azimuth of centre =

-27.452° (error = 0.16°)

Coordinates

13.413806 °

103.865161 °

Distance from mean equant   =

=  5.206 m (2.99 phyeam)

Azimuth of radius  of evection epicycle (from mean equant to true equant) =         - 125.619 °

Coordinates:

13.413748 °

103.865233 °

Distance from mean equant   = radius of evection epicycle ()

=  5.206 m (2.99 phyeam)

Diameter of epicycle = 5.98 phyeam : is is the mean width of the staircases of the Naga terrace.

Azimuth of radius  of evection epicycle (from mean equant to true equant) =  24.401°

The continuation of the radius runs through the   “Intersection Monument” IM (see “epicycle” column of Sun of Chau Srei Vibol). True azimuth of IM from the mean equant = 24.654° (error = 0.253°) Distance from centre of epicycle (mean equant) to IM = 9.973 kas = 53.856 latitude units.

With rounded-off numbers:

Distance from mean equant to IM = 10 kas = 180 phyeam

= 720 cubit = 54 latitude units

R/r = 60.06

With R = 312.677 m = distance from centre of epicycle  to IM  and

r = 5.206 m = radius of  epicycle.

A circle having the radius of the deferent and whose centre is located on the southern equant runs through the intersection of the causeway with the meridian of the libraries.

Coordinates:

13.412474 °

103.866818 °

Azimuth (as seen from observer) =

33.270 °

Distance from observer = 238.695 m

Located on capstone of central tower

0.54 m to the south west of tower’s centre

(0.44 m to south and 0.32 m to  west)

Angular error = 0.13°

Located on the circumference of “C

In the middle of the night of 14-15/04/1119, the Moon and the Sun reached the longitude observed around midnight of 15-16/04/967, eight Meton cycles earlier. Now:

- 1119 is the year of Suryavarman’s coronation (6 years after the beginning of his reign)

- 1 Meton cycle = 19 years. There are several “19” in the temple (diagram of Suryavarman’s procession scene, south side of third gallery (Mannika)

Remarks: c/Rd =  0.1095457; /Rd  = 0.021810

c +  = 31.35 m = 18 phyeam = 1 kas =  distance from centre of central tower to inner corners of first gallery

c - = 20.94 m = 12.02 phyeam

Distances of  12 phyeam were measured on the cruciform terrace. Distances of 24 phyeam were

measured on the same terrace and in the causeway libraries (Mannika).