On Apr 25, 8:15*pm, "OG" wrote:
"Les Desser" wrote in message

...





I am preparing a presentation on the Equation of Time and have been trying
to find a clear description, preferable with diagrams, of the adjustment
due to obliquity.

The explanation at the National Maritime Museum
http://www.nmm.ac.uk/server/show/conWebDoc.351 only makes sense if you
already know the answer

The best I could find was the page at
http://www.wallingfordclock.talktalk.net/Sidereal%20Time.htm but I still
find it inadequate.

The example of the bus going down the incline is good to show the slowdown
but I cannot find anything appropriate to explain the speeding up.

Has anyone seen and better presented explanations?

Does this have what you're looking forhttp://www.analemma.com/
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Are you quite finished with this late 17th century nonsense ?.

If genuine and serious investigators could spot how Piltdown man was
a hoax then the astronomical equivalent is probably the sidereal/solar
fiction first and then this hoax known as the analemma.People who
promote variations in axial inclination to the Sun just do not know
any better and shouldfd be left to their own devices,you included.

The variations in natural noon cycle arise directly from the orbital
motion of the Earth,specifically the difference between constant axial
rotation and changing orbital oreintation as a component of orbital
motion,nothing more and nothing less.The Earth is not a machine where
its components act like cogs in a machine insofar as it is fine to
inspect the individual axial and orbital motions and orientations
and determine what effects they account for but the trouble is that
the reasoning which generates the 'analemma' hoax is based on combined
axial and orbital motions as a single compound motion.I do not know
how you manage to keep the Earth tilting back and forth to the Sun
while keeping its rotational orientation fixed to Polaris,but then
again,you reason off a constant 24 hour noon cycle,determine no
variations in orbital distance ect ,ect.The Equation of Time creates
the 24 hour day out of the determination of natural noon but somehow
you turn this around to use the 24 hour day to determine the location
of the Sun in the sky or the notorious figure - 8,for an astronomer
looking on ,at least one familiar with what the Equation of Time
does,this is bewildering.

In a few sentences ,the treatise of Huygens and his exposition of the
correct method jettisons this silly analemma attached to the Equation
of Time -

"Draw a Meridian line upon a floor (the manner of doing which is
sufficiently known; and note, that the utmost exactness herein is not
necessary and then hang two plummets, each by a small thred or wire,
directly over the said Meridian, at the distance of some 2. feet or
more one from the other, as the smalness of the thred will admit. When
the middle of the Sun (the Eye being placed so, as to bring both the
threds into one line) appears to be in the same line exactly you are
then immediately to set the Watch, not precisely to the hour of 12.
but by so much less, as is the Aequation of the day by the Table."
Huygens

http://www.xs4all.nl/~adcs/Huygens/06/kort-E.html

The length of time between the natural noon cycles change,the Equation
of Time equalises to variations to 24 hours and that is it.To turn
around and then say a 24 hour clock determines natural noon or some
irrelevent variation in inclination to the Sun is a product of a silly
imagination,again,Piltdown man comes to mind.


Anyone who finds substance in these analemmas things is not an
astronomer and I do not care how established they have become as a
'fact',even a brief reading of how to determine natural noon and then
apply the Equation of Time shopuld be definitive enough.