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Astronomical dovetailing



 
 
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Old December 27th 17, 10:29 PM posted to sci.astro.amateur
Gerald Kelleher
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Default Astronomical dovetailing

The geocentric astronomers thought the Sun moved between Venus and Mars in a direct motion through the constellations and around a stationary Earth while the planets moved in the same direction as the Sun but would occasionally stop, go backwards and then return to the same direction -

https://apod.nasa.gov/apod/image/1609/MaSa2016Tezel.jpg

About 500 years ago a work called the Commentariolus by a Polish priest called Copernicus started to circulate in Europe, proposing that the Earth moved and moved faster than the outer planets thereby causing them to temporarily fall behind in view as it began to overtake them -

https://apod.nasa.gov/apod/image/011...2000_tezel.gif

At the beginning of the 17th century, another astronomer called Kepler mapped the motion of Mars against a fixed star background over an orbital period of 16 years where the Earth overtook Mars 9 times during that period -

https://upload.wikimedia.org/wikiped...retrograde.jpg

"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 dovetailing comes at the point where the older framework where the stars displayed a first annual appearance after being lost behind the glare of the Sun for a number of months displaces the obstructive perspectives of the Greeks which used the motion of the Sun through the Zodiac as a framework and still retained by Kepler when working with direct/retrograde motions -

". . . 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." Kepler 1596, Mysterium Cosmographicum


All this changes when considering the faster moving Venus and Mercury for unlike the illusionary direct/retrograde loops of the slower moving Mars, Jupiter, Saturn and so on, the inner loops are actual -

http://www.popastro.com/images/plane...ary%202012.jpg

The dovetailing comes in the the transition from evening to dawn appearance of the stars and planets. It doesn't matter if this forum is populated by theorists and assorted noiseboxes, it remains the place where information is sorted and ideas developed. It is also an achievement to partition direct/retrograde motions by perspective where the slower moving planets demonstrate loops as an illusion which the faster moving planetary loops are real and due to the motions of those planets themselves including phases.






 




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