Einstein's General Theory of Relativity demonstrates that a large mass can deform spacetime and bend the path of light. So, a very massive object, such as a cluster of galaxies can act as a gravitational lens. With this program, one can draw images to see the effect of gravitational lensing. You can easily test the effects of several parameters by changing them and redrawing the image.
Real stars and galaxies in 3D and full color. Move and look in any direction. Easy to use with keyboard shortcuts and presets. 9,000 stars (all visible stars, plus lots of nearby dim stars) and 2,400 galaxies. Displays known planetary star systems. Find stars and galaxies by name and fly to them with a keypress. Select stars by magnitude, distance, or spectral type. Select galaxies by distance or group. Has an outline of our galaxy.
