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Astronomy in antiquity
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05-01-2020 5:00pm#1If astronomers weren't aware of the motion of the stars relative to the Sun, they'd never have come up with the zodiac. The first version of that was at least 2,500 years ago.
In order to deal with objections or demonstrate how the old astronomers organised observations, easier to start a new thread than watch the present astronomical symphony drowned out.
The original framework which allows for astronomical predictions as dates within the calendar framework was based on the first seasonal appearance of a star at dawn. The Egyptians created a system of 36 grouping of constellations called Decans with a 5 day inter-calendar period and eventually refined it to include the observed fact that Sirius skips a first annual appearance by one day after the fourth 365 day cycle -
".. on account of the procession of the rising of Sirius by one day in the course of 4 years,.. therefore it shall be, that the year of 360 days and the 5 days added to their end, so one day shall be from this day after every 4 years added to the 5 epagomenae before the new year" Canopus Decree 238 BC
This is the closest to 21st century observations as when all the components of daily rotation are subtracted, a first morning appearance of a star represents its transition from the left side to the right side of the Sun as a function of the Earth's orbital motion -
https://sol24.net/data/html/SOHO/C3/96H/VIDEO/
Whereas the Egyptians were making a hybrid rotational and orbital observation, when the orbital component is isolated by a satellite tracking with the Earth's orbital motion and the ability to create permanent solar eclipse conditions, the seasonal change in position of the stars makes sense.
The Greek framework of Ptolemy inverted the older reference system where the Sun runs through the field of stars (ecliptic) from right to left as well as the 'wandering' planets -
"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
This system of Ptolemy allowed for more accurate predictions of astronomical events (eclipses, transits, ect) but because it was built on the calendar system and a 365/366 day framework, the ability to discern actual positions of planets to each other and to the central Sun is severely limiting. Copernicus and Kepler worked off this stationary 'fixed stars' background as it provided orbital to orbital comparisons but they switched the position and motion of the Sun between Mars and Venus with the moving Earth and put the Sun at the centre of all motions.
The last framework is a recent one, in this case a late 17th century RA/Dec contrivance which sent the Sun in a wandering motion along with the planets
https://sites.uni.edu/morgans/astro/course/Notes/section1/sunspath.jpg
It allowed observers to predict astronomical events, not only as dates but using a 24 hour clock, it could identify these events to precise times within the date. The Ra/Dec framework is even further removed from the original productive and creative framework as it wraps the universe up in a celestial sphere - and blanks out anything beyond daily rotation -
https://www.youtube.com/watch?v=BYy0EQBnqHI
So, the objections to the change in position of the stars from left to right of the central Sun as a demonstration of the orbital motion of the Earth is made by those who only recognise stellar circumpolar motion from horizon to horizon.
Today they even model and 'explain' the seasons using RA/Dec where the Earth has an awful zero degree axial inclination and a worse pivoting circle of illumination off the Equator -
https://apod.nasa.gov/apod/ap170319.html
Such is the era of stellarium and celestial sphere observing with a brief outline how it came about.0
Comments
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Kepler created a diagram which gauged the motions of Mars over a 16 year period and especially when the faster moving Earth overtook the slower moving planet thereby generating the familiar direct/retrograde loops using a stationary sphere of constellations arranged around the rim of the diagram -
https://upload.wikimedia.org/wikipedia/commons/e/e9/Kepler_Mars_retrograde.jpg
The same loops can be seen using modern photographs -
https://apod.nasa.gov/apod/ap181108.html
Kepler was not sketching the diagram with the Earth at the centre, he was merely applying the relationship of Mars to the stationary constellation background - two different things and ignorance of it got the later 17th century English academics into so much trouble -
"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 centre, with one extra, making nine times, while at the same time the Earth repeats its circle sixteen times " Kepler Astronomia Nova 1609
Newton comes along and assumes the diagram is geocentric ( it is still described as a geocentric framework in Wikipedia) so Newton thinks if you plonk the Sun in the middle of the diagram then the direct/retrograde loops disappear -
"For to the earth planetary motions appear sometimes direct, sometimes
stationary, nay, and sometimes retrograde. But from the sun they are
always seen direct,..." Newton
He introduced an idea of apparent motions seen from Earth and true motions seen from the Sun as absolute/relative space and motion and astronomy disappeared for 200+ years. It is what I would expect when a mathematicians tries to pretend he is an astronomer.
It gets much worse but that is the main reason RA/Dec observers can't make sense of a stationary Sun, a moving Earth and the relationship of the planets to the Sun and to each other whether they are moving faster or slower than a moving Earth. Newton's hijacking of astronomical methods and insights are pure vandalism to get his agenda that astronomical predictions are the same as experimental predictions.0 -
Today they even model and 'explain' the seasons using RA/Dec where the Earth has an awful zero degree axial inclination and a worse pivoting circle of illumination off the Equator -
https://apod.nasa.gov/apod/ap170319.html
As has been explained to you before, that is simply the view of the earth from a satellite in geosynchronous orbit. Such an orbit is necessarily above the equator, not in the plane of the ecliptic, so it keeps the North Pole at the same angle and the Sun angle appears to change, just as it does at ground level.0 -
Zubeneschamali wrote: »As has been explained to you before, that is simply the view of the earth from a satellite in geosynchronous orbit. Such an orbit is necessarily above the equator, not in the plane of the ecliptic, so it keeps the North Pole at the same angle and the Sun angle appears to change, just as it does at ground level.
Like the other person, you are going to fight this for all it is worth even though the NASA notion represents a deterioration in reasoning abilities as RA/Dec software becomes dominant -
"When does the line between day and night become vertical? Tomorrow. Tomorrow is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles" NASA ' explanation' for the seasons
https://apod.nasa.gov/apod/ap170319.html
You may as well ask when does the circle of illumination (phase) of the moon become vertical- it is completely devoid of common sense as the circle of illumination/ divisor is a component of the orbital motion of the Earth and the moon shares the same orientation as our parent planet -
https://www.jpl.nasa.gov/spaceimages/images/largesize/PIA00134_hires.jpg
The purpose of demonstrating how far gone the RA/Dec modelers actually are was showing what happens when the Sun is set in a wandering RA/Dec motion-
http://community.dur.ac.uk/john.lucey/users/solar_year.gif
It is this silly English notion that led to somebody at NASA to show a planet with a zero degree inclination and a pivoting circle of illumination as a dynamic. If it doesn't appear stupid and ugly to observers here then there is no hope. To be clear, I am demonstrating why RA/Dec observers can't stand observations from a satellite without manipulation -
https://sol24.net/data/html/SOHO/C3/96H/VIDEO/
Astronomy is a cultural thing and no dour and dull observer can ever give themselves the title of astronomer.0 -
Like the other person, you are going to fight this for all it is worth even though the NASA notion represents a deterioration in reasoning abilities as RA/Dec software becomes dominant
That video is literally the view you would see out the window of a space station in geosynchronous orbit - the sun angle at any given clock time appears to change through the year for exactly the same reason the sun angle in the sky changes through the year as seen from here on the surface of the earth.0 -
Zubeneschamali wrote: ».. the sun angle at any given clock time appears to change through the year for exactly the same reason the sun angle in the sky changes through the year as seen from here on the surface of the earth.
The Sun angle indeed !, the Sun is stationary/central while the Earth moves so making the Sun angle subservient to a non existent Earth with a zero degree axial inclination and a pivoting circle of illumination off the equator is beyond nonsense yet the seasons are described today exactly that way by RA/Dec modelers -
https://apod.nasa.gov/apod/ap170319.html
That manipulation of images is based on the notion that the Sun moves North and South crossing the Earth's Equator on the Equinox and that never existed for the original astronomers despite being stuck with the framework of Ptolemy where the Sun passes directly through the ecliptic -
http://community.dur.ac.uk/john.lucey/users/sun_ecliptic.gif
RA/Dec practitioners are so desperate to make the Earth's daily and annual traits correspond to a wandering Sun that they are will to forget size comparisons so they can have our gigantic parent star exist on daily rotational traits of the tropics of Capricorn/Cancer -
https://www.universetoday.com/wp-content/uploads/2010/05/sunearthcompared.jpg
The people most likely to find what celestial sphere theorists do as completely nonsensical don't visit these forums as most here just are identification and magnification hobbyists using RA/Dec software without any pretense to the links between the motions of the planet and Earth sciences.
If NASA had manipulated imaging to show a flat Earth it would be less offensive. I cannot imagine any reaction other than an inquiry as to what went wrong and why the origins of that monstrosity comes from the RA/Dec conclusion which not only sent the Sun wandering in a North/South sine wave against the Earth's rotational Equator but sent the Sun moving in a figure 8 -
http://community.dur.ac.uk/john.lucey/users/solar_year.gif
https://www.youtube.com/watch?v=w6WJscC44nM
The whole purpose of this thread was to demonstrate the evolution of the different reference systems where the framework closest to the motions of the planet and Earth sciences is the original one of the Canopus decree while the least accurate are Ptolemy's which allows for predicting astronomical events as dates and the late 17th century RA/Dec system which allows for the introduction of the 24 hour clock within those dates.0 -
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The Sun angle indeed !, the Sun is stationary/central while the Earth moves so making the Sun angle subservient to a non existent Earth with a zero degree axial inclination and a pivoting circle of illumination off the equator is beyond nonsense yet the seasons are described today exactly that way by RA/Dec modelers -
Try an experiment: measure the angle of the sun above the horizon at noon tomorrow. Repeat the measurement in June. The angle will be different.
That is all you are looking at in that NASA video, but you seem to entirely lack the ability to visualize, well, anything really.0 -
Zubeneschamali wrote: »Try an experiment: measure the angle of the sun above the horizon at noon tomorrow. Repeat the measurement in June. The angle will be different.
That is all you are looking at in that NASA video, but you seem to entirely lack the ability to visualize, well, anything really.
https://earthsky.org/?p=68679
I truly wish academics were perpetrating fraud but unfortunately they are manipulating imaging to suit clockwork modeling and specifically the late 17th century equatorial coordinate system that has since emerged as RA/Dec software and a celestial sphere universe.
The Royal Society people ignored the relationship between the origins of daily/annual cycles and the links to timekeeping to a close proximity and started to model planetary motions using a 24 hour clock hence these monstrosities which normal people would find hideous.
I would have about as much to say about a pivoting circle of illumination dynamic off the equator and an Earth with a zero degree axial inclination as I would a flat Earth doctrine. The only purpose it was brought up is to demonstrate where clockwork modeling has taken astronomy and humanity and that is it.
If people want to insult themselves then be my guest as it lets me know the standard of the contributor, no more or no less.0 -
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Zubeneschamali wrote: »Again, no.
If you were up there with a camera, that is what you would see too. You would have to tilt the camera (or the whole satellite!) according to the date to get the images you want to see.
I do not wish to be seen discussing the issue with what I consider many times worse than a doctrine of a flat Earther.
For everyone else they can look out at the moon in its orbital circuit of the Earth tonight with its phase and decide whether it too has a seasonal pivoting circle of illumination off its widest circumference, after all, our moon's divisor always runs parallel with the Earth's and both are perpendicular to the orbital plane at all times during their respective orbits.
https://www.jpl.nasa.gov/spaceimages/images/largesize/PIA00134_hires.jpg
Be my guest if anyone wants to follow RA/Dec modeling as even that manipulation of imaging may be too much for even those observers to stomach.
Thanks to Zubeneschamal for providing some input but there has to be a limit to what is useful and what descends into absurdity like the recent 'explanations' -
https://earthsky.org/?p=68679
Just goes to show what happens when astronomy sinks deeper into celestial sphere modeling.0 -
For everyone else they can look out at the moon in its orbital circuit of the Earth tonight with its phase and decide whether it too has a seasonal pivoting circle of illumination off its widest circumference, after all, our moon's divisor always runs parallel with the Earth's and both are perpendicular to the orbital plane at all times
Because, of course, the Moon orbits the Earth in the Ecliptic plane, not the Equatorial plane the satellite must use.0 -
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Zubeneschamali wrote: »Because, of course, the Moon orbits the Earth in the Ecliptic plane, not the Equatorial plane the satellite must use.
The celestial sphere subculture (worse than a flat Earth subculture) assigns a pivoting dynamic to the circle of illumination -
"Explanation: When does the line between day and night become vertical?"
https://apod.nasa.gov/apod/ap170319.html
The orientation of the circle of illumination always remains vertical as a component of the orbital motion of the Earth and always perpendicular to the orbital plane. It is impossible to appreciate the orbital motion of the Earth or indeed anything else without that fact.
I think it is long past overdue pointing out what the English RA/Dec has done to astronomy which links the motions of the planet to Earth sciences even when pointing out its usefulness for predicting astronomical events within the calendar and 24 hour frameworks.
I wish people with genuine astronomical aptitude visited the forum but then again, they probably don't even know they have the intuitive/perceptive qualities which make an astronomer. If they had they would share both the excitement for what is new with the dismay with what is backwards including the nonsensical pivoting divisor of a planet with a zero degree inclinatrion.
At least I don't have to deal with this in future nor those who support the imaging manipulation atrocity visited on astronomy.0 -
The Sun orbits the solar system barycentre which orbits the centre of the galaxy. It is no more stationary than anything else in the universe. If it suits a particular purpose to model the Sun as stationary, then knock yourself out.The Sun angle indeed !, the Sun is stationary/central while the Earth moves so making the Sun angle subservient to a non existent Earth with a zero degree axial inclination and a pivoting circle of illumination off the equator is beyond nonsense yet the seasons are described today exactly that way by RA/Dec modelers.
This is rich. Your "Explanation for seasonal declination" has the Earth nodding like one of those toy dogs on a car dashboard. Your "Mercury overtakes Jupiter" thread has the entire cosmos whirling past the Sun like a cloud of gnats. Despite attempting it yourself, you pretend not to understand that any frame of reference is chosen to simplify modelling in a given context.RA/Dec practitioners are so desperate to make the Earth's daily and annual traits correspond to a wandering Sun that they are will to forget size comparisons so they can have our gigantic parent star exist on daily rotational traits of the tropics of Capricorn/Cancer -
Your so-called "RA/Dec" (i.e. geocentric non-rotating) frame is useful for modelling how the sky appears from Earth, with a straightforward coordinate transformation for any given time and location on the surface of the Earth. That, after all, is where most of us live. Those living at the L1 Lagrange point may prefer your DSCOVR/EPIC or SOHO/LASCO views, depending on whether their windows enjoy a sunny aspect or not.The celestial sphere subculture...
... outnumbers the Lagrangians by a wide margin. :pac:0
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