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Kelper & Tycho - how did they come to their conclusions?
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Zubeneschamali wrote: »I would be interested to learn what you are talking about here.
Look, this is for readers who have,at the very least, looked at the founding principle which govern how the planets move against the background stars,the length of time it takes each planet to complete a circuit, the difference in luminosity and speed of each planet and all the other things which occupied the original astronomers.
". . . the ancient hypotheses clearly fail to account for certain important matters. For example, they do not comprehend the causes of the numbers, extents and durations of the retrogradations and of their agreeing so well with the position and mean motion of the sun. Copernicus alone gives an explanation to those things that provoke astonishment among other astronomers, thus destroying the source of astonishment, which lies in the ignorance of the causes." 1596, Mysterium Cosmographicum
There is a problem with an element of that description by Kepler and an incredibly important one at that yet it is a path that contemporary observers have to take but with the aid of imaging,graphics and so on. It has to do with the resolution for inner planetary retrogrades and lacking the ability to demonstrate exactly what the difference is is made even worse by the fact that nobody will lift a finger to make the important partitioning of retrograde resolutions.
Better off to just drop the matter.0 -
The Earth's orbital speed varies by only 4% in 6 months. Showing that it changes in a week with a stopwatch would be a good trick - I would like to see it done.0
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Zubeneschamali wrote: »The Earth's orbital speed varies by only 4% in 6 months. Showing that it changes in a week with a stopwatch would be a good trick - I would like to see it done.
By definition, if I say that variable orbital speed can be proved within a week then it can be done.So,what do you think of Kepler's assertion about the Equation of Time and the Earth's motion ?. Of course you need the 'Epitome of Copernican astronomy' in front of you and like the original poster said , there is little or nothing online regarding the methods by which Kepler arrived at his conclusions. This part of the proof would have been beyond Kepler as they used a different set of references based on everything moving through the Zodiac and the fact that accurate watches didn't exist.
Contemporary imaging and especially sequential imaging introduces a partitioning of retrograde resolutions between the inner and outer planets which none of the original astronomers would have been able to discern as the Earth's own orbital inputs influence observations in two separate ways. The outer planets (Mars,Jupiter,Saturn) are easy enough as the Earth overtakes the slower moving planets causing them to temporarily fall behind in view but the inner planetary retrogrades are a different story.
I ask for images an nobody lifts a finger insofar as this type of astronomy without imaging is like showing people musical notation without actually playing the music hence the disappointment.0 -
Okay okay :pac:
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mickmackey1 wrote: »Okay okay :pac:
Ah,at last so we are on the journey proper rather than it being a chore using words.
So what that time lapse footage shows is the Earth overtaking Jupiter and Saturn with the nearer Jupiter taking longer to overtake as it is moving faster along with the principle fact that with each pass of those planets they will be in a different orbital position (as will the Earth) hence the extent of retrogrades will be different and subsequently it gives a hint that planets move faster at certain times than at others. A series of APOD images of Mars will show exactly that.
As promised,there are many different paths to take and looking at the APOD footage it should be second nature by now to discern why the definition of a planet shouldn't have been disturbed from its original meaning in context of their observed motions in space as distinct from the apparent direct motion of the Sun through the same zodiac -
"Moreover, we see the other five planets also retrograde at times, and stationary at either end [of the regression]. And whereas the sun always advances along its own direct path, they wander in various ways, straying sometimes to the south and sometimes to the north; that is why they are called "planets" [wanderers]. " Copernicus
It is important for the simple reason that inner planetary retrogrades require a different set of references although Venus and Mercury also wander against the background stars as the outer planets do however as they move faster than the Earth it requires a shift in perspective. What we need next is a YouTube video entitled 'May's Planet Dance' to make this important distinction which in turns works in with proof of Kepler's insight on variable speed.0 -
This is like pulling teeth! Here:
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Zubeneschamali wrote: »I linked to an article giving you step by step instructions for reproducing Kepler's geometrical work showing that Mars orbit is an ellipse just a little while back.
I give you Kepler's own words with a description of how he looked at Mars from a moving Earth so make yourself useful and reproduce the plotting of Mars against the background stars over a 16 year period -
"Copernicus, by attributing a single annual motion to the earth,entirely rids the planets of these extremely intricate coils,leading the individual planets into their respective orbits,quite bare and very nearly circular. In the period of time shown in the diagram, Mars traverses one and the same orbit as many times as the 'garlands' you see looped towards the center,with one extra, making nine times, while at the same time the Earth repeats its circle sixteen times " Kepler
The description you give previously is contrived rubbish which can't be matched with Kepler's graphic nor modern representation of retrogrades seen as the Earth overtakes Jupiter and Saturn in that time lapse footage. This is not an excuse for the thread to turn sour as these thread are far too rare to be sabotaged when reasoning becomes intricate. Again,I would rather see the thread die than watch that happen.
Now, what do you think of Kepler's assertion of the Equation of Time and the Earth's motion and if you are not familiar with it I will type it out by hand as there is nowhere online his work is reproduced.0 -
Zubeneschamali wrote: »This is like pulling teeth! Here:
If it is like pulling teeth then you are free to withdraw as the whole point is a way to partition inner and outer planetary retrogrades by adopting two separate perspectives seen from Earth. From there you then move into variations in planetary speeds but not before then. It is a path and a visual one at that.
Now you all have to resolve the retrogrades of Venus and Mercury by assigning the orbital inputs of the Earth into those observations as distinct from outer planetary retrogrades where those planets temporarily fall behind in view against the background stars as the faster Earth overtakes them.
Anyone wish to try ?. This is all new so no need to fear this new perspective as genuine observers will love it.0 -
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Zubeneschamali wrote: »This was all old news to Kepler, since Copernicus explained it before he was born, as the picture I pasted in earlier shows.
You are fine, not even the truly brilliant Galileo understood the need to partition the perspectives between inner and outer planetary retrogrades and separate resolution -
"In the Ptolemaic hypotheses there are the diseases, and the Copernican their cure. . . . With Ptolemy it is necessary to assign to the celestial bodies contrary movements, and make everything move from east to west and at the same time from west to east, whereas with Copernicus all celestial revolutions are in one direction, from west to east. And what are we to say of the apparent movement of a planet, so uneven that it not only goes fast at one time and slow at another, but sometimes stops entirely and even goes backward a long way after doing so? To save these appearances, Ptolemy introduces vast epicycles, adapting them one by one to each planet, with certain rules about incongruous motions -- all of which can be done away with by one very simple motion of the Earth." Galileo
The kind poster who posted Jupiter and Saturn as the Earth overtakes it will find nothing about the retrogrades of Venus and Mercury even though they truly exist but require a different treatment. The YouTube video I asked you to post basically makes inner planetary retrogrades self explanatory but a number of major adjustments are needed from outer retrogrades and the way they are explained.
Maybe somebody else will try and succeed. If they do they will post another sequence of images which will help them along , this time I need the sequence of images showing the phases of Venus in an arc representing our grandstand view of the planet as it swings out from behind the Sun to its widest point from our point of view,stops and then swing in front of the Sun. Then they will come to understand the different perspectives between inner and outer retrogrades .0 -
You are fine, not even the truly brilliant Galileo understood the need to partition the perspectives between inner and outer planetary retrogrades and separate resolution
Just in case the OP is still reading, this is complete nonsense.
Far from not understanding the motions of the inner planets, Kepler was able to predict the transit of Mercury across the face of the Sun to the day, allowing it to be observed for the first time in history.
In the case of the transit of Mercury in 1631, Kepler had been extremely uncertain of the parameters for Mercury, and advised observers to look for the transit the day before and after the predicted date. Pierre Gassendi observed the transit on the date predicted, a confirmation of Kepler's prediction.[74] This was the first observation of a transit of Mercury
gkell is trying to help us get our heads around the Copernican system, which is nice of him. Apparently, he thinks it is difficult, and that lots of people have problems with it.
But gkell's posts about retrogrades are always qualitative, never any numbers. The whole point of Tycho and Kepler's work is that it is quantitative: they didn't just look at the motions of the planets, they measured them accurately, and then used a bunch of hard sums to learn stuff that you cannot learn by looking at APOD.0 -
Zubeneschamali wrote: »gkell is trying to help us get our heads around the Copernican system, which is nice of him. Apparently, he thinks it is difficult, and that lots of people have problems with it.
I am overwhelmed by the enthusiasm for the new approach to retrogrades and their resolution by using two separate perspectives seen from Earth. The rule is that the faster moving Earth overtaking the outer planets causes them to temporarily fall behind in view before they resume their motion much like being in a car moving on a roundabout sees slower moving cars in outer lanes fall behind in view.
The new approach to inner retrogrades allows us a grandstand view of the motions of Venus and Mercury as they swing out from behind the Sun and then swing back in front of the Sun. I ask for the images of Venus that we see as phases and organized as an arc to bolster the new perspective but obviously few are interested in helping promote this perspective.Zubeneschamali wrote: »But gkell's posts about retrogrades are always qualitative, never any numbers. The whole point of Tycho and Kepler's work is that it is quantitative: they didn't just look at the motions of the planets, they measured them accurately, and then used a bunch of hard sums to learn stuff that you cannot learn by looking at APOD.
'Hard sums' you say !, my goodness if you want to prove that the planet's speed varies using a stopwatch and a normal watch over a 7 day period you must follow the path laid out by the resolution of inner planetary retrogrades as the Earth's own orbital motion, in terms of an input into observations, is crucial for appreciating the observation that the Earth's speed varies each day .
It is not an imperative directed at you however readers are directed back to the YouTube video of Venus,Mercury and Jupiter over a period of a month and they can work with the Earth's own orbital motion and how it influences the picture of what we are seeing and how to deal with the motions of Mercury and Venus as they move in the opposite direction to the background stars and then move in the opposite direction, hence retrogrades.
So, images of the 'phases of Venus' anyone ?0 -
Zubeneschamali wrote: »gkell is trying to help us get our heads around the Copernican system, which is nice of him. Apparently, he thinks it is difficult, and that lots of people have problems with it.
I am overwhelmed by the enthusiasm for the new approach to retrogrades and their resolution by using two separate perspectives seen from Earth. The rule is that the faster moving Earth overtaking the outer planets causes them to temporarily fall behind in view before they resume their motion much like being in a car moving on a roundabout sees slower moving cars in outer lanes fall behind in view.
The new approach to inner retrogrades allows us a grandstand view of the motions of Venus and Mercury as they swing out from behind the Sun and then swing back in front of the Sun. I ask for the images of Venus that we see as phases and organized as an arc to bolster the new perspective but obviously few are interested in helping promote this perspective.Zubeneschamali wrote: »But gkell's posts about retrogrades are always qualitative, never any numbers. The whole point of Tycho and Kepler's work is that it is quantitative: they didn't just look at the motions of the planets, they measured them accurately, and then used a bunch of hard sums to learn stuff that you cannot learn by looking at APOD.
'Hard sums' you say !, my goodness if you want to prove that the planet's speed varies using a stopwatch and a normal watch over a 7 day period you must follow the path laid out by the resolution of inner planetary retrogrades as the Earth's own orbital motion, in terms of an input into observations, is crucial for appreciating the observation that the Earth's speed varies each day .
It is not an imperative directed at you however readers are directed back to the YouTube video of Venus,Mercury and Jupiter over a period of a month and they can work with the Earth's own orbital motion and how it influences the picture of what we are seeing and how to deal with the motions of Mercury and Venus as they move in the opposite direction to the background stars and then move in the same direction, hence retrogrades.
So, images of the 'phases of Venus' anyone ?
[ Apologies for my poor proofreading but this correction was necessary]0 -
The new approach to inner retrogrades allows us a grandstand view of the motions of Venus and Mercury as they swing out from behind the Sun and then swing back in front of the Sun.
It is a newer approach than Ptolemy's, but 1543 is scarcely new in an absolute sense.So, images of the 'phases of Venus' anyone ?
It's a biggie:
https://briankoberlein.com/wp-content/uploads/venus-phase1.jpg0 -
Phases of Venus were first observed by Galileo in 1610, and noted by him as proof of the Copernican system which predicted them, and concrete disproof of the Ptolemaic one.
Just in case gkell tells you this is news.0 -
Zubeneschamali wrote: »It is a newer approach than Ptolemy's, but 1543 is scarcely new in an absolute sense.
Thank you for posting the image so observers can see already there is a difference between inner and outer planetary retrogrades where an outer planet is brightest at the center of retrogrades as they pass the Earth at the closest distance in our mutual orbits around the central Sun whereas at the center of inner planetary retrogrades the planet disappears behind the glare of the central Sun or is at its darkest (transits).
Going back to the YouTube graphic of Mercury and Venus in motion over the course of a month it is now easy enough to see the sweeping arcs as they move around the Sun and are seen to move in the opposite direction to the background stars first and then in the same direction. This is where we depart from the perspectives of the old astronomers for they gauged all motions through the field of stars including the Sun whereas the resolution for inner retrogrades and the grandstand view of planetary motions around the Sun (shown in your image) demands a shift in perspective to account for the Earth's orbital motion and a fixed reference for the motions of Venus and Mercury.
Anyone wish to try their hand at discerning the Earth's orbital input into observations using the YouTube graphic ?. It means a shift away from the apparent motion of the Sun through the Zodiac and focusing on the apparent motions of Elnath, Castor and Pollux in sequence behind the central Sun. It is a line of sight observation using the Earth's orbital motion and another YouTube graphic entitled ' Constellations of the zodiac' helps observers come to understand what causes the stars to move along the orbital plane and behind the Sun in tandem with the actual motions of the inner planets around the Sun.
YouTube - 'Constellations of the zodiac' . It takes a bit of nimble reasoning but ultimately, as someone once said - ' society is always astonished at a new example of common sense'.0 -
This is where we depart from the perspectives of the old astronomers for they gauged all motions through the field of stars including the Sun whereas the resolution for inner retrogrades and the grandstand view of planetary motions around the Sun (shown in your image) demands a shift in perspective to account for the Earth's orbital motion and a fixed reference for the motions of Venus and Mercury.
A shift in perspective championed by Copernicus, and supported (independently) by Galileo and Kepler.
Tycho believed in a different system, but one which explained retrograde motions (and the phases of the inner planets) just as well: The Earth stationary, with the Moon and Sun orbiting it, and all the other planets orbiting the Sun.0 -
Zubeneschamali wrote: »A shift in perspective championed by Copernicus, and supported (independently) by Galileo and Kepler.
Make yourself useful and post that YouTube graphic 'Constellations of the zodiac' ( the only suitable graphic I could find presently) which shows how the Earth's orbital motion accounts for the apparent motion of ElNath,Pollux and Castor in sequence behind the central Sun thereby allowing the grandstand view of retrogrades and what they mean in terms of orbital motion,phases and so on.0 -
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Make yourself useful and post that YouTube graphic 'Constellations of the zodiac'
Here:
When are you going to get to something Kepler or Tycho actually concluded, per the thread title?
Retrograde motion was well understood by Copernicus before they were born (as his prediction of a transit of Mercury to the exact day shows), and the phases of Venus were only discovered by Galileo after the invention of the telescope, nothing to do with Kepler or Tycho's work (Galileo actually pretty much ignored Kepler and Tycho).0 -
Zubeneschamali wrote: »When are you going to get to something Kepler or Tycho actually concluded, per the thread title?
Again, I am overwhelmed by the reaction to the partitioning of retrogrades into two separate perspectives see from a moving Earth where the racetrack analogy applies to the outer planets and the grandstand view of the inner planets including phases.
Tell me, if you stood on Mars with a telescope and looked back at the Earth would you see it swing out from behind the Sun, display phases, move against the background stars and then with the same stars much like the same way we view Venus from Earth ?. Take your time with this one.
As for your question, you still have to travel that path where the Earth's orbital motion is defined by the apparent motion of the stars behind the central Sun rather than the older view of the apparent motion of the Sun through the Zodiac insofar as this line-of-sight observation becomes important in proving variable orbital speed over the course of a week using a stopwatch and a watch.0 -
Tell me, if you stood on Mars with a telescope and looked back at the Earth would you see it swing out from behind the Sun, display phases, move against the background stars and then with the same stars much like the same way we view Venus from Earth ?.
Yes, I remember reading about it in the 70s in an Arthur Clarke story, Transit of Earth, about the 1984 transit.
Maybe someone will be there to see the next one, in 2084.0 -
Here is a bit of Copernicus on the subject, with my emphasis. Copernicus understood the retrograde motion of the 5 classical planets in terms of the Earth's motion and our vantage point on it in 1543:
In this arrangement, therefore, we discover a marvelous symmetry of the universe, and an established harmonious linkage between the motion of the spheres and their size, such as can be found in no other way. For this permits a not inattentive student to perceive why the forward and backward arcs appear greater in Jupiter than in Saturn and smaller than in Mars, and on the other hand greater in Venus than in Mercury. This reversal in direction appears more frequently in Saturn than in Jupiter, and also more rarely in Mars and Venus than in Mercury. Moreover, when Saturn, Jupiter, and Mars rise at sunset, they are nearer to the earth than when they set in the evening or appear at a later hour. But Mars in particular, when it shines all night, seems to equal Jupiter in size, being distinguished only by its reddish color. Yet in the other configurations it is found barely among the stars of the second magnitude, being recognized by those who track it with assiduous observations. All these phenomena proceed from the same cause, which is in the earth's motion.0 -
this line-of-sight observation becomes important in proving variable orbital speed over the course of a week using a stopwatch and a watch.
So, you are going to somehow time how fast the sun is moving against the background stars?
So, maybe set your watch for midday, and use your stopwatch to time the difference between clock noon and actual noon (assuming you have a sextant handy to give you true noon).
Hmm, you'll have to separate changes due to the change in the Earth's orbital speed from changes due to the shape of the Earth's orbit and the inclination of the Earth's axis.
And the effect you are looking for is only around 0.15% in week. The max change in noon is 16 minutes, the difference will be a max of 1.5 seconds in a week. No way you can measure true noon that accurately.0 -
Zubeneschamali wrote: »Yes, I remember reading about it in the 70s in an Arthur Clarke story, Transit of Earth, about the 1984 transit.
Maybe someone will be there to see the next one, in 2084.
When we look out at Venus we see its graceful arc as it moves through space and around the Sun with the phases shown in that image you presented previously an affirmation that we have a grandstand view of that planet's motion around the Sun . I would need a proper affirmation from a few other readers that the Earth as seen from Mars would also swing out and back in front of the Sun with observed phases and as a means to demonstrate that this partitioning of retrogrades is a new approach.
This is not an exercise in pulling teeth but a journey and so far precious few have made it far enough along that path to distinguish that relative planetary speeds are used to resolve retrogrades of the outer planets as the faster moving Earth causes the outer planets to temporarily fall behind in view whereas inner planets are a grandstand view.0 -
I would need a proper affirmation from a few other readers that the Earth as seen from Mars would also swing out and back in front of the Sun with observed phases and as a means to demonstrate that this partitioning of retrogrades is a new approach.
I suppose 471 years is relatively new, compared to Ptolemy's scheme, which is 1864 years old.0 -
Zubeneschamali wrote: »I suppose 471 years is relatively new, compared to Ptolemy's scheme, which is 1864 years old.
Look, the description of retrogrades by Copernicus was as amazing for me when I first saw it as it was for the few of his contemporaries that understood it, the comments of Galileo and Kepler being among those who love the common sense solution, however, the retrogrades of Mercury and Venus are not due to the orbital motion of the Earth. The retrogrades of Jupiter and Saturn and their apparent backward motion against the background stars are an illusion created by the faster moving Earth but the motion of the Earth is insufficient to account for the motion of Venus and Mercury as they move against the background stars and then as those planet swing in front of the Sun the move in retrograde as that YouTube graphic adequately shows.
So, the faster Earth seen from Mars will be observed to move out from behind the central Sun to its widest point and against the direction of the background stars before turning in with phases attached to that observation. I am prepared to let this new insight be accepted slowly before moving on to variable orbital speeds and other wonderful avenues to pursue.
Thanks for supplying the images so far,there are many more I would request before this newbie status is lifted yet I would feel there is enough already in front of readers and observers that they would provide lively discussions using all these new visual tools.
Without the affirmation of a few other readers as regards to what the Earth would look like from Mars as it orbited the Sun it all looks dictatorial instead of the enjoyable exercise that it actually is.0 -
the retrogrades of Mercury and Venus are not due to the orbital motion of the Earth.
Not just to the Earth's motion, obviously you also have to consider Venus's own motion, which is more rapid than ours. But you have to consider the motion of Mars and Jupiter also: if they weren't moving, they would just wobble about in a parallax ellipse, not the track with retrogrades which we see.
Here's Venus:
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I am going to park this for a few days so observers can become accustomed to the motion of Venus as it is seen from Earth and especially its phases which should delight observers for what they are. I do need,for a number of important reasons, a few readers to affirm that the Earth when seen from Mars would display the same type of phases as it swings out to its widest point and then swings in front of the Sun as distinct from the alternative principle which govern outer planetary retrogrades.
One of the reasons for a necessary affirmation by a number of people is that the partitioning of retrogrades in this manner is entirely new and although I commend the other person for providing the bulk of the images and graphics so far, it is not a matter of shoving this new approach down people's throats but rather a journey that some more than others may wish to take. The original astronomers were astonished with the common sense resolution which Copernicus applied to retrogrades however it turns out that the input of the Earth's orbital motion only accounts for outer retrogrades and has minimal influence on retrogrades as applied to Venus and Mercury. I can easily demonstrate that this is a new way but this is not a matter of priority but rather how far observers will go to appreciate or ignore what modern imaging can do.
I have noticed that gaming among young people totally saps the imagination in an unproductive way in much the same way chewing gum doesn't substitute for a substantive meal so it is up to adults to apply their imagination properly when looking at these graphics and images as an aid to what actually goes on outdoors. There is no time for grandstanding but there is always time for a grandstand view of the planets and the motion of our planetary neighbours. The next step is up to observers here in this forum whether to move along the path further or go back to an historical path with a dead end to it, I personally hope it is the former decision.0
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