Refracting telescope focus, results in a non-inverted and upright image. Galileo’s best telescope magnified objects about 30 times. Because of flaws in its design, such as the shape of the lens and the narrow field of view, the images were blurry and distorted. Despite these flaws, the telescope was still good enough for Galileo to explore the sky. The Galilean telescope could view the phases of Venus, and was able to see craters on the Moon and four moons orbiting Jupiter. Parallel rays of light from a distant object (y) would be brought to a focus in the focal plane of the
Craters of the Moon (geothermal site) in diameter. The most powerful fumarole observed at Craters of the Moon occurred December 1967. It had a heat output of 116 MW. Currently, only one of the craters has a mudpool. Here the gases (mainly HS) react with water to form sulphuric acid. This reacts with the rocks, turning it to clay. When there is water present, this forms the grey coloured mudpools “that bubble and burp as steam and gas escape through them”. Much of the ground at Craters of the Moon is warm or hot. This of course affects the vegetation. Only few species can survive. One