Is Venus 'the astronomical metronome of our world'?

1
Good morning,

On pages 41 - 42 of Messrs. Christopher Knight & Robert Lomas'

The Book of Hiram

one reads:
"... when viewed from the Earth, the planet Venus is the most accurate indicator of the time of year available in the solar system. Every eight years it marks a point when the solar calendar, the lunar calendar and the sidereal calendar all coincide to within a few minutes [of time, arc?]. After exactly forty years, when Venus competes five of its eight-year cycles, it synchronises to within fractions of a second [of time, arc?), providing a calendar and clock that was used to set the time of day until the 1950s when even more accurate atomic clocks were invented.

Put simply: Venus is the metronome of our world. ... Against the background of the zodiac [which - tropical, equal-sign 'sidereal' or constellations?] Venus completes a five-pointed star shape every eight years and returns to its precise [definition of precision?] starting place after forty years." [added]
The authors show a summary table of this cycle on page 42.

My question - addressed to those members with sufficient astronomical knowledge - is rigorously restricted to astronomy. Most of the book otherwise seems to me to be a verbose 'much ado about little'.

I have attempted with mitigated outcomes to reproduce this cycle using the animation functions of astrology software. Although the basic cycle indeed exists, i cannot confirm the great precision asserted in the quotation.

Best regards,

lihin
Non esse nihil non est.

2
Hello
I thought this link might possibly be of some help:
http://eclipse.gsfc.nasa.gov/transit/ca ... talog.html

I don't have the astronomical credentials you require, but out of interest, I had a look using Solar Fire, testing with 40x365.25 day (solar) years and 40xsolar return, both sidereally and tropically (without precession). For the 365.25 year, the pattern is there as you say, but the precision of return to "its precise starting place" is not. Tropically, the occurrences are about 3?15-20' out, sidereally about 2?45-50' out. The solar retrun is further out of sync, and using a sidereal year would also make the retruns all slightly further out. Using a 360 day year (sidereal or solar days), which I thought might be a possibility, does not give a regular pattern at all, as far as I can see.

That book looks rather dubious, as you imply.

Graham

Theme with variations

3
Good morning,

Thank you very much, Dr Graham, for the very interesting and useful link. The following text indicates a mundane cycle of the geocentric Venereal Nodes more than thrice a complete geocentric procession of the fixed stars (emphasis added):
The position of the orbital nodes of Venus with respect to Earth are [sic!] slowly changing with time. Five thousand years ago, transits occurred around May 21 and November 19. At present, the transits occur within a day of June 7 and December 9. In about 1500 years, the transits will occur during Earth's solstices (June 21 and December 22). This trend in the shift of transit dates is readily apparent in the catalogue below. Over a period of approximately eighty thousand years, the transit dates will migrate forward one complete cycle through the seasons.
There are relatively few geocentric planetary phenomena that resemble plodding along a straight, narrow path at nearly constant velocity, for example H?lios on the ecliptic. Most of the planetary patterns far more resemble intricate, rhythmic dances symbolised by Shiva, Dionysus and their Consorts. :D

Best regards,

lihin
Non esse nihil non est.