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On Apr 4, 1:52 am, "TR Oltrogge" <troltro...@xxxxxxxxxxx> wrote:
> "tomcee" <tomcees...@xxxxxxxxx> wrote in message
>
> news:24b3d18e-ac7f-46e9-a0a8-3ba9057ff035@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> > Given a table of sunset times, such as:
> <snip>
> > Has anyone determined the basic functions contained within this
> > 'Sunset function'? Given the basic functions, I can then calculate the
> > constants.
> > Thanks in advance for your help,
> > TomCee
>
> My reply is going to infuriate everyone because of its horrendous
> complexity,
I think the words you are looking for is either 'convoluted' or
'contrived', instead of complicated you repeat the same old
falsehoods with no central theme jumping all over the place from Ra/
Dec terns to geocentric ones or using celestial sphere geometry. to
justIify heliocentric and axial rotational motions.In lieu of any real
astronomical authority in existence to seperate the terms and untangle
the contrived mess created in the late 17th century,here are the basic
working principles -
Geocentric - The Earth centered solar system (Antiquity to the
Copernican discovery)
Many assume an Earth centered Universe however any astronomer worthy
of the name would simply look at how the original heliocentric
astronomers viewed the precepts of their antecent geocentric
counterparts -
"With regard to Venus and Mercury, however, differences of opinion are
found. For, these planets do not pass through every elongation from
the sun, as the other planets do. Hence Venus and Mercury are located
above the sun by some authorities, like Plato's Timaeus [38 D], but
below the sun by others, like Ptolemy [Syntaxis, IX, 1] and many of
the modems. Al-Bitruji places Venus above the sun, and Mercury below
it. " COPERNICUS
http://webexhibits.org/calendars/yea...opernicus.html
Heliocentric system (Copernicus to present) - the orbital motion of
the Earth between Venus and Mars by using orbital motion to resolve
the observed behavior of the other planets ,their periodic times to
resolve the placement of the Earth between the 225 day orbital period
of Venus and the 687 day period of Mars with axial rotation as a means
to resolve the observed daily cycle.
Ra/Dec or celestial sphere approach (Flamsteed to present) - the
practice of using celestial sphere geometry to justify axial and
orbital motions of the Earth where the stars have an undefined
equidistant geometry to the Earth.It was originally created to resolve
determination of terrstrial longitudes for marine navigational
purposes by Flamsteed but was extended by Newton to heliocentric
reasoning.
Many are inclined to use bluster which others mistake for confidence
or authority however there is always hope that there are actually
genuine people who are not afraid of the unfamiliarity with the
difference between geocentric and heliocentric reasoning as it was
orginally understood,the actual principles which keep clocks in sync
with the daily cycle at 24 hours/360 degrees,the observational
convenience of the Ra/Dec system,the actual principles which
distinguish timekeeping and structural astronomy from the
observational convenience ,the modifications required to bring
perceptions up to speed with modern observations and many,many more
realistic approaches to honor human reasoning.
but I thought I would brush up on my vector algebra and solve
> this problem by...
>
> (1) considering the earth's orbit as an ellipse
> (2) using Kepler's "equal area for equal time" rule of orbit speed
> (3) general mapping of 3D coordinates from one basis (Earth's lat/lon grid)
> to another (Earth's orbital plane 23.5 degrees oblique)
> (4) the astronomer's publishing of GMT for perihelion and summer solstice
> (5) looking iteratively for when the vector from the sun to the observer is
> basically perpendicular to the vector from the earth's center to the
> observer
>
> Well, after working almost a month I've got a 'C' program that seems to get
> within 6 minutes of the U.S. Navy's published times. I actually learned a
> lot about vector operations. For now I'm going to put this thing to rest,
> but here's the code...
>
> =============================================================================================================
>
> /*
> SUNSET.C a program to calculate the time of sunset for any given latitude
> and longitude, year, and day
> of the year. It uses vector algebra as much as possible.
>
> Sunset occurs when a line from the sun (considered a point source) runs
> tangent to the earth and touches
> earth exactly at the point of the observer's latitude and longitude
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