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  #41  
Old March 8th 18, 07:26 PM posted to sci.astro.amateur
Bill[_9_]
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Default Polar astronomy

On Thu, 8 Mar 2018 09:00:57 -0800 (PST), wrote:

On Thursday, March 8, 2018 at 4:39:48 PM UTC, Quadibloc wrote:
So I give Oriel a much better score than 100% wrong; to me he seems to be
very nearly right, even if some subtle distinctions apply.


The distinctions are not subtle.

How long does it take Io to go from "Left of Jupiter" (as Gerald would say) to "Right of Jupiter" and back to "Left of Jupiter" ? Galileo estimated it as 42.5 hours. This is so tiny compared to the orbit of either the Earth or Sun that it is effectively the same as the period of Io's orbit around Jupiter. By contrast, Venus orbits the Sun in 224 days, but does not return to its greatest Eastern elongation for 584 days because of the Earth's orbital motion.

Io is in retrograde for very close to half of each orbit of Jupiter, Venus for about 42 days of those 584 or 7% of the time.

Gerald continually posts a photomontage of the phases of Venus around a central Sun (without background stars or dates) and pretends that this represents something or other we might observe in the sky. It is baloney. Since he has never in his life actually looked at the sky and bases his ignorant rants on random youtube clips and jpgs, he knows no better, but you certainly do.


Agree.
I can't think of any professional level endeavor where that his sort of
lackadaisical, sloppy, piecemeal approach would provoke anything but
scorn from any audience.

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  #42  
Old March 8th 18, 07:44 PM posted to sci.astro.amateur
Quadibloc
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Default Polar astronomy

On Thursday, March 8, 2018 at 11:26:42 AM UTC-7, Bill wrote:

I can't think of any professional level endeavor where that his sort of
lackadaisical, sloppy, piecemeal approach would provoke anything but
scorn from any audience.


I am not defending him from the charge of being a crackpot, because that
he obviously is, but simply noting that when he occasionally, if only by
accident, gets something right it should be acknowledged.

His view that astronomy should be a quasi-mystical activity is obviously
to be dismissed.

His idea that we are anti-Copernican if we relate the Earth's rotation
directly to the inertial frame of the fixed stars is wrong and silly.

But, in connection with his mistaken framework, when he points out that
there is a distinction between the way retrograde motion is manifest in
the inferior planets and the superior planets - well, he is pointing out
something real. In the case of the inferior planets, we are indeed
looking at those planets' real orbits around the Sun - although it would
be more apparent from, say, the Moon, without an atmosphere, than on
Earth, where it was once thought that Venus was two distinct bodies, the
evening star and the morning star.

With Mars or Jupiter, their real orbits around the Sun have retrograde
motion added to them; with Venus and Mercury, the retrograde motion is
caused by their real orbital motion on the opposite side of the Sun.

He may impute a different significance to this fact than we would, but
the fact is real none the less.

So even if he is getting parts of the story wrong, since he is here
mentioning something quite real, to say he is ludicrously wrong, 100%
wrong, or saying the exact opposite of the truth just isn't accurate.

John Savard
  #43  
Old March 8th 18, 07:45 PM posted to sci.astro.amateur
Gerald Kelleher
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http://www.popastro.com/images/plane...ary%202012.jpg

20th /July/2010 to 20th/January/2012 found in the jpg image address.

It is not enough to pronounce that the illusory loop of Mars or indeed any of the slower moving planets with larger orbital circumferences than the Earth are resolved though an overtaking perspective while leaving the direct/retrogrades of the faster moving planets unattended.

All the whining directed at me doesn't alter the fact that direct/retrogrades of the slower moving planets is accepted separately to the perspectives of Venus and Mercury. If somebody can insert an illusory loop into the actual loop of Venus in the 18 month sequence of images above then good for them, everyone else can stay with an animated graphic long enough to watch Venus and Mercury move in one direction against the stars until they reach their widest point before turning back in front of the Sun where they move in the opposite direction -

https://www.youtube.com/watch?v=MdFrE7hWj0A


http://www.theplanetstoday.com/

As Venus and Mercury are currently are an evening appearance they are to the left of the Sun and will eventually overtake us before becoming a morning appearance to right of the Sun due to our slower motion.

So we do see Venus and Mercury both as actual loops and in direct/retrograde.

  #44  
Old March 8th 18, 08:35 PM posted to sci.astro.amateur
[email protected]
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Posts: 306
Default Polar astronomy

With Mars or Jupiter, their real orbits around the Sun have retrograde
motion added to them; with Venus and Mercury, the retrograde motion is
caused by their real orbital motion on the opposite side of the Sun.

That remark about how you know better? I apologize and withdraw it.
  #45  
Old March 8th 18, 11:14 PM posted to sci.astro.amateur
Gerald Kelleher
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Posts: 1,372
Default Polar astronomy

On Thursday, March 8, 2018 at 6:26:42 PM UTC, Bill wrote:


I can't think of any professional level endeavor where that his sort of
lackadaisical, sloppy, piecemeal approach would provoke anything but
scorn from any audience.


"This apparent erratic movement is called "retrograde motion." The illusion also happens with Jupiter and the other planets that orbit farther from the sun."

https://mars.nasa.gov/allaboutmars/nightsky/retrograde/

So much for scorn when they already make the distinction without promoting how direct/retrogrades of the faster planets play out against the slower moving Earth. That distinction first happened in this newsgroup so I shrug and enjoy the fact that they at least strive to make the distinction without filling in the details for Venus and Mercury which requires an entirely different approach.

I guarantee that any teacher who teaches their students the principles which distinguishes the illusory loop of Mars from the actual loop of Venus by analogy or by use of imaging will get a satisfaction rarely experienced. It is because the direct/retrograde modification is new that it gives the talented plenty of leeway to express the principles as they see fit.







  #46  
Old March 9th 18, 06:05 AM posted to sci.astro.amateur
Bill[_9_]
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Posts: 306
Default Polar astronomy

On Thu, 8 Mar 2018 10:44:16 -0800 (PST), Quadibloc wrote:

On Thursday, March 8, 2018 at 11:26:42 AM UTC-7, Bill wrote:

I can't think of any professional level endeavor where that his sort of
lackadaisical, sloppy, piecemeal approach would provoke anything but
scorn from any audience.


I am not defending him from the charge of being a crackpot, because that
he obviously is, but simply noting that when he occasionally, if only by
accident, gets something right it should be acknowledged.

His view that astronomy should be a quasi-mystical activity is obviously
to be dismissed.

His idea that we are anti-Copernican if we relate the Earth's rotation
directly to the inertial frame of the fixed stars is wrong and silly.

But, in connection with his mistaken framework, when he points out that
there is a distinction between the way retrograde motion is manifest in
the inferior planets and the superior planets - well, he is pointing out
something real. In the case of the inferior planets, we are indeed
looking at those planets' real orbits around the Sun - although it would
be more apparent from, say, the Moon, without an atmosphere, than on
Earth, where it was once thought that Venus was two distinct bodies, the
evening star and the morning star.

With Mars or Jupiter, their real orbits around the Sun have retrograde
motion added to them; with Venus and Mercury, the retrograde motion is
caused by their real orbital motion on the opposite side of the Sun.

He may impute a different significance to this fact than we would, but
the fact is real none the less.

So even if he is getting parts of the story wrong, since he is here
mentioning something quite real, to say he is ludicrously wrong, 100%
wrong, or saying the exact opposite of the truth just isn't accurate.

John Savard


Of course he's not 100% wrong. He's 110% wrong. Behavior-wise.

Seriously, when someone states the impossible - then they're telling us
that their assertion isn't to be taken as statment of fact. IMO, Niall's
remark was a bit of hyperbole/sarcasm - aka: frustration from dealing
with our resident Troll/crackpot.

As I see it, the way Gerald has repeatedly misportrayed people here for
years, and all this trolling of his... I'm afraid I have run out of
empathy for him.
  #47  
Old March 9th 18, 08:00 AM posted to sci.astro.amateur
[email protected]
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Posts: 306
Default Polar astronomy

On Thursday, March 8, 2018 at 6:45:27 PM UTC, Gerald Kelleher wrote:
20th /July/2010 to 20th/January/2012 found in the jpg image address.
If somebody can insert an illusory loop into the actual loop of Venus in the 18 month sequence of images above then good for them


Here you a http://www.davidcolarusso.com/astro/

Set the date to July 2010 and advance one frame at a time.

You are welcome.
  #48  
Old March 9th 18, 10:43 AM posted to sci.astro.amateur
Gerald Kelleher
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Posts: 1,372
Default Polar astronomy

Back in 2005 when I proposed that the 26 mile spherical deviation of the planet is linked to plate tectonics via differential rotation of the fluid interior (across latitudes) ,the response of the community was to throw the kitchen sink at rotation without actually mentioning zonal flow across latitudes. I see the same here with direct/retrogrades and the necessary distinction between the faster and slower moving planets so what looks like an improvement becomes a mess in the hands of those who are just chancing their arm.

While the geological proposal remains speculative although supported by visible clues on the surface crust or by using planetary comparisons between the Earth and Venus both dynamically and geologically, the direct/retrograde topic in front of observers is 100% verifiable. I suppose I should kick up a fuss but with the wider community reluctantly pursuing the correct path but the fuller picture will eventually make it out.

So, the only means to stop the Sun moving through the constellations so our parent star acts as a central reference for the motions of Venus and Mercury is to adopt the oldest astronomical framework where the stars 'come in season' or in dynamical terms - they are far enough to one side of the Sun to emerge as a dawn appearance. Of course it introduces a slightly more complicated narrative than just comparing the illusory loop of Mars with the actual loop of Venus but observers shouldn't be overly concerned with the complication. The fact is proof of the Earth's orbital motion is the transition of the stars from left to right of the Sun and to ignore that is pretty small.







  #49  
Old April 9th 18, 10:51 AM posted to sci.astro.amateur
Quadibloc
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Posts: 6,925
Default Polar astronomy

On Thursday, March 8, 2018 at 10:01:02 AM UTC-7, wrote:
By contrast, Venus orbits the Sun in 224 days, but does not return to its
greatest Eastern elongation for 584 days because of the Earth's orbital motion.


That's certainly a good point.

The contrast isn't so striking in the case of Mercury, of course.

If you look at a diagram of the apparent motion of Mars or Jupiter, you see a
circular trail of loops. The circle part - if plotted against the starry
background - has the same period as the actual orbits of those planets.

A diagram of the apparent motion of Venus or Mercury is also a circular trail of
loops. But now the general circle moves through the zodiac... once a year, along
with the Sun. So the *loops*, which lead to retrogrades, are due to Venus and
Mercury orbiting the Sun, and the overall motion is due to the Earth's motion
changing our viewpoint. (How could it be otherwise? Venus and Mercury are always
on the same side of the Earth as the Sun, so their orbital motion *can't* take
them through a full circle of the Zodiac from our point of view by itself.)

That is a fact. I'm not saying that you have to accept that Oriel is right that
this is an important fundamental distinction between retrogrades of inferior and
superior planets. But there is the old saying that one must give even the Devil
his due; and that he has managed to get one thing right, for a change, should be
cause for celebration.

John Savard
  #50  
Old April 9th 18, 10:57 AM posted to sci.astro.amateur
Quadibloc
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Posts: 6,925
Default Polar astronomy

On Monday, March 5, 2018 at 1:19:07 PM UTC-7, Gerald Kelleher wrote:
If you can distinguish between the open-ended illusory loop of Mars from the
closed actual loop of Venus you have already come to understand what Galileo and
the original Sun centered astronomers did not and that does nothing to diminish
those astronomers. I do not even ask observers to know why their perspectives
were incomplete but it does help to know why Venus ad Mercury do not trace out
open-ended loops as previous views held -


You are expressing a genuine astronomical fact here, but you have also made an
error.

With the superior planets like Mars and Jupiter, the general apparent motion is
due to their actual orbits, while the loops, that give rise to retrograde
motion, are due to the Earth's motion.

With the inferior planets like Mercury and Venus, the general apparent motion is
due to the Earth's motion around the Sun, while loops, that give rise to
retrograde motion, are due to their own actual orbits.

That is true. And their orbits around the Sun are closed ellipses (neglecting
details like perturbation). But the loops due to those closed orbits in their
*apparent* paths, which also include the results of the Earth's orbit, are still
open-ended - not closed.

John Savard
 




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