Re: Mixed Coordinate conversion - ra from long and dec


John Carruthers wrote:
oriel36 wrote:
I hope you learned that it is not a good idea to base the orbital
motion of the Earth on a system which uses 3 years of 365 days and 1
year of 366 days.

Your celestial sphere geometry relies on the return of a star in 23
hours 56 min 04 sec and it requires a leap day correction to work for
in your system.

While you dream tonight of Kepler my 'scope will be tracking the
heavens accurately.

http://mitpress.mit.edu/journals/pdf/POSC_13_1_74_0.pdf

Kepler's representation known as the Panis Quadragesimalis (Page 86) is
just one of those exquisite astronomical jewels that most intelligent
people would enjoy with a little effort or familiarity.

The two dates of 1580 and 1596 represent the 18 orbital cycles of Earth
in comparison to the orbital cycles of Mars where retrogrades are
plotted against the stellar background.Using these comparisons,Kepler
would use the periodic time comparisons to argue for heliocentricity in
terms of the motion of the Earth between Venus and Mars *.

No telescope is required to enjoy what Kepler did and how he reasoned
as an extension of the original Copernican insight but it will be there
for all to see.



Be assured they will turn without your supervision.
Any coordinate system we aply is purely arbitrary, use the most
convenient for your purpose.

Pseudo-authority is fine and indeed I marvel at the casual and carefree
manner in which 'arbitrary' is assigned to celestial phenomena.My turn.

The 24 hour clock system and its calendrical extension are almost two
seperate system's but the core principle is based strictly on the
pre-Copernican return of the Sun to noon where the Equation of
correction is applied to facilitate the seamless transition from one 24
hour day to the next.The exquisite adaption by the heliocentric
astronomers was to apply the Equation of Time correction to the idea
that the Earth's axial rotation is an independent motion,something the
pre-Copernican astronomers knew nothing about.

The calendrical extension has no astronomical basis save that it is a
convenience based on celestial sphere averaging,roughly 1461 days.Its
basic format of a star returning to a meridian in 23 hours 56 min is
conditioned by the 1461 calendrical cycle of 3 years of 365 days and 1
year of 366 days.



If we stood on the sun a heliocentric
system would undoubtedly work. We do not. We are on earth (not sure
about you though) and geocentric co-ordinates work just fine.

Everyone deserves a chance,you can turn to page 86 and affirm that
Kepler is making orbital comparisons between Mars and Earth using the
stellar background as a reference for Mars and taking the Earth's
orbital cycle in years as a gauge .The working language of Kepler,as it
is for all heliocentric astronomers is an orbitally moving Earth in
accounting for observed planetary motion.It is all made very easy today
with images of the position of the planets against a fixed background
and rendered into time lapse footage,like so


http://antwrp.gsfc.nasa.gov/apod/image/0112/jupsatloop_tezel.jpg



http://antwrp.gsfc.nasa.gov/apod/image/0112/JuSa2000_tezel.gif




They get
our probes to their targets and our 'scopes stay centred. We are all in
step exept you.....
jc

Indeed you are all in step,that is abundantly clear.I do however
require at least a few to gauge correctly that Newton is not in step
with the original reasoning of Copernicus and Kepler,not even with the
Ptolemaic astronomers -

" For to the earth planetary motions appear sometimes direct, sometimes
stationary, nay, and sometimes retrograde. But from the sun they are
always seen direct," NEWTON

The correct answer is,of course,that planetary heliocentric motion is
seen directly from Earth -

http://antwrp.gsfc.nasa.gov/apod/image/0112/JuSa2000_tezel.gif

Climate and geological concerns are far more important than keeping you
telescopes in sync with celestial sphere geometry,as long as nobody
tries to justify the celestial sphere they can happily carry on with
astrophotography.But,and there is a but,astrophotography is just a
minor facet of astronomy and presently a feebleminded and destructive
facet having allied itself with empirical theorists.





-----------------------------------------------------------------------------------------------------------------------------
*
Epitome Of Copernican Astronomy by Johannes Kepler


Finally by what arguments do you prove that the centre of the Sun which
is at the midpoint of the planetary spheres and bears their whole
system - does not revolve in some annual movement,as Brahe wishes,but
in accordance with Copernicus sticks immobile in one place,while the
centre of the Earth revolves in an annual movement.


Argument 10


" The 10th argument,taken from the periodic times, is as follows; the
apparent movement of the Sun has 365 days which is the mean measure
between Venus' period of 225 days and Mars' period of 687
days.Therefore does not the nature of things shout out loud that the
circuits in which those 365 days are taken up has a mean position
between the circuits of Mars and Venus around the Sun and thus this is
not the circuit of the Sun around the Earth -for none of the primary
planets has its orbit arranged around the Earth,as Brahe admits,but the
circuit of the Earth around the resting Sun,just as the other
planets,namely Mars and Venus,complete their own periods by running
around the Sun."


Johannes Kepler

.

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