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First sign of Polar dawn



 
 
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  #1  
Old August 20th 17, 08:58 AM posted to sci.astro.amateur
Gerald Kelleher
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Default First sign of Polar dawn

https://www.usap.gov/videoclipsandmaps/spwebcam.cfm

This observation is bound up with the Great Eclipse as the motion of the Earth along the orbital plane causes the stars to move from left to right behind the central Sun hence poor notions like parallax are really unhelpful when taking into consideration that the Earth's orbital motion turns the surface slowly and unevenly. The annual event of polar sunrise about 4 weeks away is a consequence of that surface rotation.
  #2  
Old August 20th 17, 11:51 AM posted to sci.astro.amateur
Quadibloc
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Default First sign of Polar dawn

On Sunday, August 20, 2017 at 1:58:16 AM UTC-6, Gerald Kelleher wrote:
the motion of the Earth along the orbital plane causes the stars to move from
left to right behind the central Sun


That is true. That's why different constellations are visible at night during different seasons of the year.

hence poor notions like parallax are really unhelpful when taking into
consideration that the Earth's orbital motion turns the surface slowly and
unevenly. The annual event of polar sunrise about 4 weeks away is a
consequence of that surface rotation.


I'm not at all sure what parallax has to do with it.

At the Earth's North Pole, when you look straight up, you will find Polaris,
even if it will only be visible during the six months of night at that pole.

When the Sun is visible from the North Pole, it will appear to circle around you
once every 24 hours - and when it isn't, the stars will appear to circle around
Polaris once every 23 hours, 56 minutes, and four seconds.

The discrepancy is indeed due to the fact that the Earth orbits the Sun.
Different stars are behind the Sun during different parts of the year, as you
note.

And the North Pole isn't pointing towards the direction that could be called
"ecliptic north". The Earth's axis is inclined by about 23 degrees away from
being perpendicular to the plane of its orbit.

This inclination has a direction - so, as the Earth orbits around the Sun,
sometimes the Sun is in that direction, and sometimes the Sun is away from that
direction. The line going from the Earth to the Sun points to different stars,
but the North Pole always points to Polaris.

In the system of Tycho Brahe, the Earth indeed would need to rotate on an annual
basis as well as a daily one - there would be a daily rotation on the axis, and
an annual precession of that axis around a second axis perpendicular to the
ecliptic.

In the Copernican system, though, it doesn't look like a rotation.

Of course, it doesn't look like a rotation when one thinks of the stars as being
painted on the walls of a room which has a tabletop orrery in it. I think I
understand that you view that as an imaginary perspective, and instead you
contend for a viewpoint which both acknowledges the Copernican fact that the
Earth moves and yet which also resembles that of Tycho Brahe in some respects -
because it acknowledges that we are on the Earth.

John Savard
  #3  
Old August 20th 17, 12:44 PM posted to sci.astro.amateur
Gerald Kelleher
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Default First sign of Polar dawn

Using the $50 American webcam, the first signs of dawn are appearing at the South pole until sunrise appears on the September Equinox -

https://www.youtube.com/watch?v=okw6Mu3mxdM

The Great American Eclipse marks a watershed as it represents an affirmation of Galileo's contention -

“You cannot teach a man anything, you can only help him find it within himself.”
― Galileo Galileo



  #4  
Old August 20th 17, 05:47 PM posted to sci.astro.amateur
Gerald Kelleher
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Default First sign of Polar dawn

The South pole telescope station webcam is spectacular at the moment despite the quality of the image -

https://www.usap.gov/videoclipsandmaps/spwebcam.cfm

  #5  
Old August 22nd 17, 07:57 PM posted to sci.astro.amateur
[email protected]
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Default First sign of Polar dawn

On Sunday, August 20, 2017 at 11:51:28 AM UTC+1, Quadibloc wrote:

I have nothing against this person however a few remarks are necessary at this juncture given that many of the remaining contributors to this forum have been here since its infancy. The emergence of empiricism in astronomy also heralded the tendency to create science fiction which eventually became science fantasy in the early 20th century. The overlap between the magnification/identification RA/Dec framework with its predictive capabilities and Royal Society theoreticians always contained the elements of fiction by exploiting the intricacies of astronomical arguments, in this case the usefulness of the former was misused by experimental practitioners and their clockwork solar system.

The usefulness of predicting when and where an eclipse occurs was never meant to carry the idea of predicting 'climate change' among many things but unfortunately one was conflated with the other via 'universal theories' or 'laws of nature'.

The remaining contributors, at least some of them, would have seen the Usenet evolve and it has transferred over to the comment sections of most newspapers but what most today call 'trolling' is really a lowering of intellectual standards. I steered clear of contributors like the one responding to me in this thread as they live in a fantasy world and I have noticed a few other contributors stayed clear for the same reason. Unlike the magnification enthusiasts who still retain some semblance of astronomical discipline, those who drift from fantasy characters to real characters are the worst case scenario.

Where the work of the original Sun centered astronomers and the empirical mutations meet there is a huge amount of work to be done, in this case basically extracting science fiction from propositions which in themselves are not entirely accurate and are deficient, for instance the partitioning of inner and outer planetary retrogrades by perspective.


  #6  
Old August 25th 17, 10:20 PM posted to sci.astro.amateur
Gerald Kelleher
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Default First sign of Polar dawn

With a little over 3 weeks and perhaps about 23 degrees of orbital surface rotation before the Sun comes into view for the one and only time over the course of an orbit, even the webcams now look okay _

https://www.usap.gov/videoclipsandmaps/spwebcam.cfm
 




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