You can alsophotograph planetsat short focal lengths on a star tracker, as seen in the image of the planet Venus and the moon below. As long as the mount has been polar aligned and balanced, longer focal lengths (up to about 500mm are practical) The portable, free-spirited nature of a...
In his experiments with gravity, Isaac Newton showed how the motion of each planet in the solar system results from the combined gravitational pull of the Sun and of all the other planets, each contributing according to their mass and distance from the o