Expérience de Bradley

L’observation de l’aberration de la lumière de James Bradley (1725)

(a) montre une observation d’une étoile sur une Terre immobile tandis que la figure (b) montre une observation d’une étoile sur une Terre en mouvement.

Edit and compile if you like:

\documentclass[tikz,border=10pt]{standalone}
\usepackage{tkz-euclide}
\begin{document}
\begin{tikzpicture}
  % To draw the telescopes
      \newcommand{\telescope}[1][2]
                 {
                   \draw[#1] (-0.25,0) -- (-0.25,2) -- (0.25,2) -- (0.25,0) -- cycle;
                   \draw[#1] (-0.05,0) -- (0.05,0) -- (0.05,-0.5) -- (-0.05,-0.5) -- cycle;
                 }
      %figure a
      \tkzDefPoint(0,5){E}

      \telescope[shift={(0,0)}, rotate=0];

      \draw[red,->,>=stealth] (E) -- (0,-0.5);

      \filldraw (E) circle (0.05);

      %The labels
      \node[above] at (E) {$S$};
      \node at (0,-1.5) {(a)};
      
      %figure b
      \tkzDefPoint(5,5){Strue} % The star at its true position
      
      \tkzDefPoint(3.2,5){Sapp} % The star at its apparent position
      \telescope[shift={(5,0)}, rotate=20];
      \telescope[shift={(5.8,0)}, rotate=20,dashed];
      \draw[red,->,>=stealth] (Sapp) -- (5.19,-0.5);
      \draw[blue,->,>=stealth] (Strue) -- (5.19,-0.5);

      \filldraw (Strue) circle (0.05);
      \filldraw (Sapp) circle (0.05);

      
      \draw[<->,>=stealth] (6.5,2) -- (6.5,-0.5);
      \draw[<->,>=stealth] (5.19,-1) -- (6,-1);
      \draw[<-,>=stealth] (3.5,1) -- (4.65,1);

      % The labels
      \node[above] at (4.6,2) {$B$};
      \node[above] at (5.6,2) {$A$};
      \node[above] at (Strue) {$S_{\textrm{Vraie}}$};
      \node[above] at (Sapp) {$S_{\textrm{Apparente}}$};
      \node[left] at (3.5,1) {$v$};
      \node[right] at (6.5,1) {$c\Delta t$};
      \node[below] at (5.595,-1) {$v\Delta t$};

      % The angle theta
      \begin{scope}
        \clip (Sapp)  -- (Strue) -- (5.19,-0.5) -- cycle;
        \draw [red] (5.19,-0.5) circle (3.5);
        \node[above,red] at (4.5,3) {$\theta$};
      \end{scope}
      
      \node at (4.85,-1.5) {(b)};
    \end{tikzpicture}
\end{document}