<canvas id="sky"></canvas>
const canvas = document.getElementById('sky');
const ctx = canvas.getContext('2d', { alpha: true });
const speedSlider = document.getElementById('speed');
const showOrbits = document.getElementById('showOrbits');
const showMoonOrbits = document.getElementById('showMoonOrbits');
const showLabels = document.getElementById('showLabels');
const showKuiper = document.getElementById('showKuiper');