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| View Original: | Venus geocentric orbit curve simplified Line (pentagram).svg (592x591) | |||
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| Keywords: Venus geocentric orbit curve simplified Line (pentagram).svg A simplified plot of the position of Venus with respect to the Earth i e geocentric perspective For this graphic Venus and the Earth are assumed to be in coplanar concentric perfect circular orbits around the sun and Venus' and Earth's orbital periods are assumed to be in an exact 8 13 ratio so that the size of Venus' orbit with respect to the Earth's is set as the cube root of 8²/13² by Kepler's third law or about 0 7234876 AU The resulting 5-fold symmetric curve is sometimes called a pentagram though it has little resemblance to a conventional 5-pointed star The innermost loops near the center are where Apparent retrograde motion is observed See File Venus geocentric orbit curve simplified pentagram svg for this plotted as a series of points instead of a continuous curve and see File Venus pentagram png for an alternative more astronomically-correct less simplified plot The SVG was generated by means of the following self-written vector PostScript source code <pre> 306 396 translate 3152 dup scale 9 setlinewidth /angq add 18 mul dup 8 div exch 13 div def /getx angq sin 550 mul exch sin 397 91817792197 mul sub def /gety angq cos -550 mul exch cos -397 91817792197 mul sub def /pi 6 28318530718 def 0 -152 08182207803 moveto 0 1 2079 /q exch def q 0 getx q 1 getx q -1 getx sub pi div add q 0 gety q 1 gety q -1 gety sub pi div add q 1 getx q 2 getx q 0 getx sub pi div sub q 1 gety q 2 gety q 0 gety sub pi div sub q 1 getx q 1 gety curveto for closepath stroke showpage EOF</pre> 2016-03 AnonMoos <gallery>File Venus geocentric orbit curve simplified pentagram svg Series of points</gallery> Orbit of Venus Astronomical diagrams 5-fold dihedral symmetry Images with PostScript source code | ||||
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