If you want to see the stars, why not build a telescope that touches the sky? This might have been astronomer, Johannes Hevelius’ thinking when he built a 150-foot long telescope. (That’s about as wide as a football field.) From his rooftop observatory, Hevelius used his telescope to observe solar and lunar eclipses, sunspots, planets, and the Moon. When you look at the Moon, you may see shadows or dark spots that suggest the existence of mountains. Hevelius calculated with high accuracy the approximate height of several lunar mountains based on their shadows. Unfortunately, Hevelius’s observatory, along with his books, records, and notes, were destroyed by a fire on September 26, 1679. Luckily, this woodblock print survived and illustrates what his telescope looked like.