verbatimtex %&latex \documentclass{article} \usepackage{fourier} \begin{document} etexbeginfig(1); % excentricité, demi-grand axe, demi-petit axe numeric e,a,b; e = 0.2; a = 100; b = a * sqrt(1 - e * e) ; % ellipse path el; el = (fullcircle xscaled 2a yscaled 2b) rotated -78; pair S,T; % soleil vrai S = point 5.2 of el; % terre T = (sqrt(a**2-b**2),0) rotated -78; % axes draw ((-1.1a,0) -- (1.1a,0)) shifted T; draw ((0,-a) -- (0,1.3a)) shifted T; draw el; % ligne des apsides draw ((-a,0)--(a,0)) rotated -78; % marque des angles path t[]; t1 = reverse (((fullcircle scaled 30 rotated -78) shifted T) cutafter (T--(T shifted (20,0)))); t2 = ((fullcircle scaled 20 rotated -78) shifted T) cutafter (T--S); drawarrow t2; drawarrow t1; draw T--S; % le soleil label(btex $S$ etex, 1.1S); draw S withpen pencircle scaled 6pt withcolor (1,1,0); label.urt(btex $v$ etex,point 3 of t2); label.lrt(btex $\varpi$ etex,point 1 of t1); label.urt(btex $\gamma$ $0^{\tiny\circ}$ etex,(.92a,0)shifted T); label.urt(btex $90^{\tiny\circ}$ etex,(0,(1+e)*a)shifted T); label.ulft(btex $180^{\tiny\circ}$ etex,(-a,0)shifted T); label.llft(btex $270^{\tiny\circ}$ etex,(0,(-1+e)*a)shifted T); dotlabel.llft(btex $T$ etex, T); dotlabel.urt(btex $A$ etex, (-a,0) rotated -78); dotlabel.llft(btex $P$ etex, (a,0) rotated -78); endfig; end