## Re: [sl] Re: Archaeogeodesy Study

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• James, man, keep still long enough to answer a question! You re jumping around all over the place, and never resolving anything - at least not to me. In a
Message 1 of 3 , Mar 30, 2006

James, man, keep still long enough to answer a question!  You're jumping around all over the place, and never resolving anything - at least not to me.

In a message dated 3/30/06 6:09:49 PM GMT Daylight Time, jqjacobs@... writes:
mikebispham@... wrote:

"    > Sorry to be slow; why the 'of course'?  Do English feet
> relate in a significant way to arc seconds?

Good question.  Your not slow here; that was an allusion to
assumptions made by some.  This issue was discussed years ago in
discussion groups.  My momory of the "facts" goes like this:

There is a "coincidence' of considerable accuracy.  First, bear in
mind that in some cultures (i.e., China), the earth was divided by
days per year/orbit instead of 360 degrees.  Now, given equatorial
circumference = 131479775.378 feet (modern standard for feet) based on
current ocean level.

131479775.378 / 360 degrees = 365,221.6
131479775.378 / days per year  = 359,979.7 feet
131479775.378 / days per orbit = 359,965.7 feet

Again, this calculation uses the modern definition of the foot.  Study
of ancient metrology entered the debate, in particular, "The Origin of
English Measures" now online at:

http://www.metrum.org/measures/english.htm    "
This is Livio C. Stecchini, who needs to learn how to order his work, and provide references.  I'm not saying I know better, but I didn't learn much from reading him, and at the moment regard the story of Henry XIII yard as probably as good as any.  Lets leave that one... and accept that we'll have to work with any measure at all, and use proportional values to make sense of the data.

"    So, there is that aside.  Onward, to the thread itelf..    "
Stop!  If you think there is a relationship between English feet and arc seconds, explain it to us.  A summary will take you five minutes, and we'll be able to give you feedback and perhaps deeper information.

> Perhaps it would be helpful if you could fill
> in some details and data for us ....

That would fill a good-sized book.  Start here:
http://jqjacobs.net/astro/archaeogeodesy.html

and read the four part series first.    "

No can do - time short... concise answers will bring best results....  Responding to my direct questions with straightfoward short answers even better.

"    > Sighting of the moon would require a good
> vertical plane surface at right-angles to
> its course (the celestial plane) ....

It requires darkness, so the position of the moon can be observed in
relation to fixed celestial reference.  That is sidereal time. "

Ok, the moon can be clocked against a background of stars.  What does that tell us?  What would be the point of doing so?

One subtopic at a time:

Earth diameter calculations
Related unit details
Solar/lunar predictions (calendricals)
Planetary predictors (same, but more specialised)

To which of these things does the moon-against-stars technique relate, and how (in each case if more than one) does it apply.

" And duration is required to average the motion over time.  The moon is not
orbiting at a constant speed.  The apogee:perigee ratio is about 7:8,
considerable ellipticity in the orbit, hence changing speeds.

> ... providing 'clocks' that might be used to
> relate instantaneous time from one site to another
> This would be necessary - you'd need a fixed point
> in time to clock the different moon positions ...

You are thinking like sailors on a moving ship that does not know
where they are.  I've had this discussion before, and this view is
commonly held, but not actually fully considered.  Here is what I
posted elsewhere:

=============
<<<< The million dollar question, is, of course, how would they have
measured (longitude) ... I can see no mechanism that pre-dates the
high accuracy sea going clock ... >>>>

No - now you've leaped onto navigation, which wasn't part of the original conversation at all.

You have however answered, I think, my question by telling me about the moon-stars-background business.  Never mind lattitude.

As you point out....

"    It is an entirely different problem.

On land, you know where you are and your position is fixed. You can
take all the time you want and need, and you can look to the sky and
see what time it is. So,

1.) you know where you are,
2.) you have all the time in the cosmos,
3.) your not going anywhere unless you decide to move your positioned
point,
4.) you know what time it is.

You know what the sideral time is at any given point...

A very wise man in China taught me one BIG lesson. Zu Chongzhi
(430-510 CE) measured gnomen shadows for 24 day spans around the
solstice, and calculated mean values to refine the value of the
tropical year. It gave me great joy to read that. I realized, on land
you can observe the moon for, oh, say, 18.613 years, and calculate
mean values too, but not from a moving ship at sea.

Yes...  so... for what purpose?

I'd recommend using the Newark Great Circle and Marietta, or
Stonehenge, Thornborough, Avebury, Newgrange, Tara. Good ditches for
water-leveling helps, as do standing stones for references. Or natural
rock in a high, dry desert. Or all of them at once! Of course, you'd
want to know how far apart these sites are. "

Eh?  How would a stonehenge observer obtain data from Newark!?

"    Better stated, you'd end up knowing how far apart these points are. I know I have. "

Purpose....
=============

"    The real insight is in understanding the role of lunar calendrics and
long durations of observations.  The moon is a foresight, an arm
moving against the face of a clock.

Well, 'lunar calendrics' defined, purpose explained would be good, but... Yes.... so...?

> ... machinery would enable the circumference
> of the earth to be read  ...

All you need to do this is a measured, north-south line and two
vertical poles set plumb (or a rope in a tree).  You compare the
shadow lenghts and do the simple geometry, two angles and one side
determine the third angle, and presto, the circumference is
extrapolated.  This is so simple, it is no wonder the size of the
earth was known long before history begins.  Erostosthenes, the
librarian, was just reporting ancient knowledge (before that library
was burned).

Yes, yes....

" > I've swum around your website (only a little)
> http://jqjacobs.net/astro/aegeo.html  ... To your...
> "Questions Posed."

> ... Cultures ... respond in similar ways entirely
> independently.  That said, of course ideas move too,
> and by different means.

Mike,

Precise, indeed.  And the modules I've proposed and found to be of
utility can be independently discovered.  "

'Modules'?   Unit lengths? Applications?

" They are inherent in lunar calendrics and time keeping by astronomic reference.  This is why I
defined them as analytic tools in the first instance, way back in the
80s.  I did not expect the trans-Atlantic results.   "

What transatlantic results?

" But there they are, posing the questions they do. "

...?

Sorry if I appear rude James, but really, I'm only trying to understand and help.  Do try to tell us your _main point and or points_ and explain why you hold it/them and what your reasoning and evidence is.  Lets have a start - first-things-first topic that we can subsequently build on.

Best

Mike

• ... Likewise, time too short to rewrite here the pages already written. JQ
Message 2 of 3 , Mar 30, 2006
mikebispham@... wrote:

> James, ... keep still long enough to answer a question! ...
> Perhaps it would be helpful if you could fill
> in some details and data for us ....

I wrote: Start here:

> No can do - time short...

Likewise, time too short to rewrite here the pages already written.

JQ
• Finally getting to a reply. Too many projects :-). ... There are coincidences. I made a pun. ... Calendars and ephemerides, foundations of knowledge,
Message 3 of 3 , Apr 2, 2006
Finally getting to a reply. Too many projects :-).

mikebispham@... wrote:

> Stop! If you think there is a relationship between
> English feet and arc seconds, explain it ...

There are coincidences. I made a pun.

> Ok, the moon can be clocked against a background of stars.
> ... What would be the point of doing so?

Calendars and ephemerides, foundations of knowledge, prediction of
tides (= eclipses), place determination, point positioning,

> Sorry if I appear rude James, but really, I'm only
> trying to understand ... tell us your main point
> and or points and explain ...

Mike,

Understanding is not condensed soup. Sorry if it's a
chore, but you will have to start reading at:

http://jqjacobs.net/astro/archaeogeodesy.html

JQ

PS. E-group etiquette includes cropping post quotes to only the
relevant material you are responding to. Does everyone a favor.
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