Re: analemmatic guy

On 4 Mar, 21:55, "oriel36" <geraldkelle...@xxxxxxxxx> wrote:
"If you looked at the Sun at the same time each day, from the same
place, would it appear at the same location in the sky? If the Earth
were not tilted, and if its orbit around the Sun were perfectly
circular, then, yes, it would."

http://solar-center.stanford.edu/art/analemma.html

Tell me analemmatic guy what the analemma looks like at the Equator
over the course of a year seeing you are intent on proposing axial
tilt as a component in the Equation of Time.

The variations in the Sun's position is a consequence of the orbital
path of the Earth and unless you are entirely stupid,I would not
recommend that you include the apparent arc of the Sun across the sky
as a factor in the Equation of Time,no figure 8,no nothing,in fact
take up birdwatching where you can be less destructive.

The Equation of Time is a global phenomena and has nothing whatsoever
to do with axial tilt but it has quite a lot to do with rotation and
the rate of change of the orbital orientation of the planet due to
orbital motion.

Now,the human devised creation of the 24 hour day may be of little
consequence to celestial sphere astrologers and their pseudo-dynamic
of a variable tilting Earth but it would be nice to see somebody who
can actually appreciate the brilliance of our ancestors in creating
the 24 hour day and applying it to axial rotation as a clock
correlation.

First go outside, yes, you can do it, then observe the sun with your
own eyes instead of reitterating distorted imaginings.
Have you ever made an accurate sundial ? (Google for 'Shadows').
If you have trouble comprehending the article just come back here and
ask for help.
Remember Jezza, this model works for a great many intelligent,
curious, people. It fits and accounts for the observations. On the
other hand of course there's you...

http://myweb.tiscali.co.uk/moonkmft/Articles/EquationOfTime.html
The Analemma. At noon, according to mean clock time (GMT if on the
Gweenwich zero meridian), the sun will be almost due south. Its
altitude will vary substantial throughout the year, as its declination
varies from -23.5 to +23.5 degrees. It will also generally vary
slightly in position, to the east or west of due south, due to the
mean clock time not being the same as sundial time. If one could
support a camera stationary throughout the year, pointing due south,
and upwards at an angle of about 40 degrees to the horizontal; and
expose the film very briefly at exactly noon (mean time) every few
days, whenever the sky was clear, throughout the year, then the
multiple images of the sun on the resultant multi-exposure photograph
would form a very narrow, elongated, figure-of-eight, with the top
(northern) lobe smaller than the bottom (southern) part. Such a figure
is known as an analemma. In actual fact, if one could travel westwards
along the equator at a uniform speed such that we took exactly 24
hours to arrive back where we started (more than 1000 miles per hour),
then the Sun would not appear to move noticeably during the course of
the day. If however, we continued for a whole year, the Sun would
appear to trace out this slender figure-of-eight we call the analemma.

If instead, one points the camera in a different direction, and takes
the exposures at a different time of day, e.g. late afternoon, one
will get a similar effect, but the figure-of-eight will not be
vertical, as here. An analemma for Mars can be seen here, from a
multiple exposure photograph taken in late afternoons on Mars by the
Pathfinder Project. This, instead of being a figure-of-eight, is
shaped like a pear. As stated above, due to the eccentricity of its
orbit, the Equation of Time on Mars just follows one cycle per Martian
year, and the analemma does not cross over itself.

There is an encyclopedia article about the analemma here, which shows
the Earth's and Mars' analemmas.
http://en.wikipedia.org/wiki/Analemma.

Have a ball and keep up the trolling.
jc

.

Relevant Pages

  • Re: Congratulations guys !
    ... the night sky. ... so do the stars. ... Because the Moon revolves around the Earth about once a month, ... In turn, because the Earth revolves around the Sun once a year, and ...
    (sci.astro.amateur)
  • Re: Congratulations guys !
    ... "Astronomers use sidereal time as a way to keep track of the direction ... the night sky. ... Because the Moon revolves around the Earth about once a month, ... In turn, because the Earth revolves around the Sun once a year, and ...
    (sci.astro.amateur)
  • Re: RA question
    ... sky. ... But the Earth also revolves around the Sun. ... sync with axial rotation when it was promoted by Copernicus as the ...
    (sci.astro.amateur)
  • Re: Dangerous places for nuke use...
    ... The fact that the Earth rotates rather ... than standing still as the Sun goes around it makes no direct difference ... Scattering is what makes the sky so blue, ... Is it true that a red sky at morning, ...
    (rec.arts.sf.science)
  • Re: 2-4 more inches of snow on Sunday!!!
    ... edge of an ice sheet looking at its reflection in the water while mood ... that the big yellow ball of fire in sky called the Sun that is ... the planet and till the day when earth is finally swallowed up by it. ...
    (soc.culture.irish)