Venus,
moving in an orbit smaller than the Earth's, must always appear to be much
in the same direction as the Sun. She may sometimes be to the left of the
Sun, sometimes to the right, but never more than 48° distant from him,
and at her greatest distance crosses the meridian between three and four
hours before or after him. The result is that Venus can only be seen in
the morning before sunrise or in the evening after sunset, and lf she is
very near the Sun she cannot be seen at all, although very clear-sighted
people may sometimes see her near the Sun in broad daylight. We have no
mention of any such observation at Babylon. Venus is therefore in succession:
1.
The evening star, Greek Hesperos and Latin Vesper;
2.
invisible;
3.
the morning star, Greek Phosphoros, Latin Lucifer;
4.
invisible;
5.
and then the evening star again.
The
synodic period or mean duration of the four phases is 584 days, while the
length of the individual phases is variable. Five of these periods will
last 2,920 or, more exactly, 2,919 1/2 days; eight solar years are 2,922
days; 99 lunar months are 2,923~ days. The result is that a particular
phase of Venus recurs at the same season of the year and month at intervals
of eight years; only the return is not absolutely exact, for it falls about
2 1/2 days earlier in the solar year and 4 days earlier in the lunar month.
From this it follows that if a conjunction of Venus with the Sun falls
two days after new moon, it may be expected to fall two days before new
moon eight years later, but will not fall near new moon again till 64 years
after the first date, when eight intervals of four days will have amounted
to a complete month. At this recurrence the conjunction will fall 17 days
earlier in the solar year, so that if the exact position of the calendar
months in the solar year is not fixed, a phase of Venus may recur in the
same month and on or near the same day of the month at intervals of 8,
56, 64, and even 112 or 120 years. When Venus at conjunction is between
the Earth and the Sun, she is said to be at inferior conjunction; when
the Sun at conjunction with Venus is between her and the Earth, Venus is
said to be at superior conjunction.
-
- Langdon & Fotheringham
The
Venus Tablets of AMMIZADUGA
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