Uriel's machine.

From Wiki:
Uriel's Machine: The Prehistoric Technology That Survived the Flood is a best selling book published in 1999 by Christopher Knight and Robert Lomas.The book's name is derived from a character of the same name in the Book of Enoch. In Knight and Lomas's interpretation of the Book of Enoch, Uriel warns Enoch about the impending flood, giving him instructions for building a form of solar observatory for the purpose of preserving advanced knowledge into a time of global disaster by teaching him the movement of the Sun against the horizon over a period of time, which Enoch then records in detail in the Book of the Courses of the Heavenly Luminaries.

According to  Christopher Knight and Robert Lomas, Uriel's machine is a 'horizon declinometer'. The fundamental premise is, an asteroid or comet approaching earth is more likely to hit us, if it is in the plane of the ecliptic. As the position of the sun, moon and planets show us where the ecliptic is, an Uriel's Machine, with its numerous portals and windows could therefore act as an early warning system - allowing the position of comets and asteroids to be noted and compared against the position of the ecliptic.

The purpose of this blog post is to give you some information about how, if you so wishes, you could build an Uriel's machine! I am not going to debate in any detail if this would help you to determine the danger presented by objects heading towards Earth.

Uriel's Machine starts at the fourth portal, which contains the Vernal equinox.

And the sun rises from that portal and sets in the west, and returns to the east and rises thirty mornings in the third portal and sets in the west in the third portal

The sun's shadow is always shortest when the sun is at its highest position and points North/South. So place a pole where you wish to begin, and mark the shadow lengths with pebbles. When you have the shortest shadow mark a line from the base of the stick to the end of the shortest shadow. 

This is a north-south line, the meridian. 

Draw a line 90 degrees across this to indicate the equator, the East/West line.

When the sun rises at the equinox, its declination is zero. This means that the Sun's path, the ecliptic travels along the equator -it isn't higher or lower than the equator at the equinoxes.

So, Portal 4 begins when the sun rises in the east, on the celestial equator at declination zero.

Uriel's machine is described as a 'horizon declinometer'.

Declination is the angle of the sun in relation to the celestial equator. The declination of the sun is caused by the oblique angle of earth's rotation in relation to the sun. It changes with the position of the earth in its orbit around the sun over the course of the year. 

The declination of the Sun at the equinox  =  90 degrees minus your latitude.

Add +23 for summer solstice.

Minus 23. at the winter solstice.

In other words, the Sun is 23 degrees above the equator at midsummer, and 23 degrees below it at midwinter.  With all the angles in-between as the year progresses. The declination of the sun effects its rising and setting point, and how high it is when it crosses the meridian - the North/South line. 

Latitude also effects the rising and setting points so an Uriel's machine in France would be different to one made in the Orkney islands.

Back to 'the machine'. 

1. Standing at the centre of the circle, mark the east. The first marker indicates the equinox.
2. The second marker of  the fourth portal is positioned about thirty days latter (because there are 90 days between the vernal equinox and the solstice). 
3. Thirty days latter, another marker (so now you have portal 5).
4. And one more marker in another thirty days to complete portal 6.

So far so good?

The rate of change in the sun's declination is faster at the equinox, and slower at the solstices. So the portals are sub-divided.

1. 12 smaller divisions closest to the equinox.
2. 8 sub-divisions for the portal between April and May
3. 4 subdivisions for the solstice portal, number six.

Portals three to two and one are made by the same method as the sun moves back to an east rising at the autumn equinox, and down to the south east rising at the midwinter solstice. 

Criticism.
Uriel's Machine is described as an horizon declinometer. It is true to say that a star will set in the same numbered portal and window on the western side, as the one it rose in, on the east. But the declinometer will not show you how high the star will travel as the earth turns.

The equator line from east to west does not pass directly over your head unless you are on the equator - on the earth. The celestial equator is at an angle to the zenith, dependent on your latitude. Here, 90 - 52 (lat) = 38. 

A large post could be placed in the south of the circle so that its top touches the sky at more or less 38 degrees as seen from the centre of the circle by someone of average height. Only then would I have any idea how high the celestial equator appears to be?

On the other hand, you could use Uriel's machine it to create some rules, such as the Pleiades will rise today from portal 6 as the sun sets in portal 3 (I have made that up!)

The marker for the ecliptic is the zodiac. Hence names such as Tropic of Capricorn, or Point Aries. The ecliptic tracks through the twelve signs of the zodiac, so there isn't any need to use Uriel's machine to judge where a light in the sky is, simply note when and where in the constellation you see it! The Book of Enoch was written in Aramaic, a 'Mesopotamian' script and language, most of the signs still used to day had their origins there. 

By 4000 BC we had got food animals and plants brought to Britain from the East, along with the first of the Long Barrows at Coldrum. And we probably had got some ideas about the constellations and the ecliptic...There are many henges, sites that were once timber circles and at least one example of prehistoric trilithons in Britain. 

Were they used in any way similar to an Uriel's machine?

John North in particular was much taken with starry alignments, especially pairs of stars - one rising as another sets- and he sees possible alignments of this nature in the positioning of long barrows. He also considered the possibility that henges were used as a way for a Neolithic astronomer (a Druid?) to use the bank as a way to determine azimuth and declination.

Basically, there is no need to re-invent the zodiac, and knowledge of the moon is the best way to predict eclipses. And the moon is difficult! If Newton had reason to curse the Moon and it's perturbations, we can be pretty sure that trying to find ways to predict what the Moon is up to would have been a problem people would keep on trying to solve.

Stonehenge seems to me to be more about the Midwinter moon than anything else. 

One interesting task that could be carried out with Uriel's machine as described, is to notice the difference in timing between equinox and solstice and to consider what this tells us about the position of the Sun... perigee and apogee.

---
The description used by Lomas and Knight from The Book of Enoch.

And the sun rises from that portal and sets in the west, and returns to the east and rises thirty mornings in the third portal and sets in the west in the third portal.
And on that day the night becomes longer than the day, and night becomes longer than night, and day shorter than day till the thirtieth morning, and the night amounts exactly to ten parts and the day to eight parts.

And the sun rises from that third portal and sets in the third portal in the west and returns to the east, and for thirty mornings rises in the second portal in the east, and in like manner sets in the second portal in the west of the heaven.
And on that day the night amounts to eleven parts and the day to seven parts.
And the sun rises on that day from that second portal and sets in the west in the second portal, and returns to the east into the first portal for one-and-thirty mornings, and sets in the first portal in the west of the heaven.

And on that day the night becomes longer and amounts to the double of the day: and the night amounts exactly to twelve parts and the day to six.

And the sun has (therewith) traversed the divisions of his orbit and turns again on those divisions of his orbit, and enters that portal thirty mornings and sets also in the west opposite to it.  And on that night has the night decreased in length by a †ninth† part, and the night has become eleven parts and the day seven parts. And the sun has returned and entered into the second portal in the east, and returns on those his divisions of his orbit for thirty mornings, rising and setting.

And on that day the night decreases in length, and the night amounts to ten parts and the day to eight. And on that day the sun rises from that portal, and sets in the west, and returns to the east, and rises in the third portal for one-and-thirty mornings, and sets in the west of the heaven. On that day the night decreases and amounts to nine parts, and the day to nine parts, and the night is equal to the day and the year is exactly as to its days three hundred and sixty-four.

And the length of the day and of the night, and the shortness of the day and of the night arise--through the course of the sun these distinctions are made (lit. 'they are separated'). So it comes that its course becomes daily longer, and its course nightly shorter.

And this is the law and the course of the sun, and his return as often as he returns sixty times and rises, i.e. the great luminary which is named the sun, for ever and ever. And that which (thus) rises is the great luminary, and is so named according to its appearance, according as the Lord commanded. As he rises, so he sets and decreases not, and rests not, but runs day and night, and his light is sevenfold brighter than that of the moon; but as regards size they are both equal.